diff --git a/packages/ui/cypress/fixtures/knownMultisigs.ts b/packages/ui/cypress/fixtures/knownMultisigs.ts
index c07b2c22..a6da17dd 100644
--- a/packages/ui/cypress/fixtures/knownMultisigs.ts
+++ b/packages/ui/cypress/fixtures/knownMultisigs.ts
@@ -8,5 +8,17 @@ export const knownMultisigs = {
       testAccounts['Multisig Member Account 1'].address,
       testAccounts['Multisig Member Account 2'].address
     ]
+  },
+  'multisig-with-unknown-transaction': {
+    address: '5CNUH7K6RgXqEo4zK3i9cEDX1CDozJkmvuK6cRZ3z8ovY5CN',
+    pureAddress: '5GeQBX3xT9oV5PVjnuakx6tRFEwxKGqnohfduWpp4MVt1uC6',
+    purePublicKey: '0xcaa3c7393cdc0d101797a216222c1d44a92bdc3653f6d0fadfad040adad4e091',
+    threshold: 2,
+    hashOfUknownCall: '0x49478dcdda5a328ba4918e8faca68f347462f41903c461122a36b7c51483768f',
+    callData: '0x000060556e6b6e6f776e205472616e73616374696f6e2054657374',
+    signatories: [
+      testAccounts['Signatory 1 Of Multisig With Unknown Tx'].address,
+      testAccounts['Signatory 2 Of Multisig With Unknown Tx'].address
+    ]
   }
 }
diff --git a/packages/ui/cypress/fixtures/testAccounts.ts b/packages/ui/cypress/fixtures/testAccounts.ts
index 57947466..42cda194 100644
--- a/packages/ui/cypress/fixtures/testAccounts.ts
+++ b/packages/ui/cypress/fixtures/testAccounts.ts
@@ -61,5 +61,19 @@ export const testAccounts = {
     name: 'Funded Account 3 Chopsticks',
     type: 'sr25519',
     mnemonic: 'bottom drive obey lake curtain smoke basket hold race lonely fit walk//chopsticks/3'
+  } as InjectedAccountWitMnemonic,
+  'Signatory 1 Of Multisig With Unknown Tx': {
+    address: '5C5RWYL7zoV6V2vdwXENSpSzWHXUxyhHBrEzhfySdQmkiF9d',
+    publicKey: '0x008c37659f858da7ec1416ce01b975af4c6eb5931805047d173d63123174a74e',
+    name: 'Signatory 1 Of Multisig With Unknown Tx',
+    type: 'sr25519',
+    mnemonic: 'various sun sell patch follow stove warfare worry cupboard kick wise wild'
+  } as InjectedAccountWitMnemonic,
+  'Signatory 2 Of Multisig With Unknown Tx': {
+    address: '5DAA5LQP8C4Cus1caXr3rwDa5LuPCJmXeoj3HrCUWEpGUV7g',
+    publicKey: '0x3064b82d59077c4d2d7b924b72e63fb9b829b5cd0706b9236c35b79ffa89995b',
+    name: 'Signatory 2 Of Multisig With Unknown Tx',
+    type: 'sr25519',
+    mnemonic: 'canyon narrow primary zoo purpose double rice faculty critic embark trophy economy'
   } as InjectedAccountWitMnemonic
 }
diff --git a/packages/ui/cypress/support/page-objects/modals/txSigningModal.ts b/packages/ui/cypress/support/page-objects/modals/txSigningModal.ts
new file mode 100644
index 00000000..0ea4986f
--- /dev/null
+++ b/packages/ui/cypress/support/page-objects/modals/txSigningModal.ts
@@ -0,0 +1,8 @@
+export const txSigningModal = {
+  body: () => cy.get('[data-cy=modal-tx-signing]'),
+  callHashLabel: () => cy.get('[data-cy=label-call-hash]'),
+  approveButton: () => cy.get('[data-cy=button-approve-tx]'),
+  rejectButton: () => cy.get('[data-cy=button-reject-tx]'),
+  callDataInput: () => cy.get('[data-cy=input-call-data]'),
+  callInfoContainer: () => cy.get('[data-cy=container-call-info]')
+}
diff --git a/packages/ui/cypress/support/page-objects/multisigPage.ts b/packages/ui/cypress/support/page-objects/multisigPage.ts
index a4c6f42b..13e2d9ff 100644
--- a/packages/ui/cypress/support/page-objects/multisigPage.ts
+++ b/packages/ui/cypress/support/page-objects/multisigPage.ts
@@ -6,8 +6,6 @@ export const multisigPage = {
   optionsMenuButton: () => cy.get('[data-cy=button-options-menu]'),
   editNamesMenuOption: () => cy.get('[data-cy=menu-option-edit-names]'),
   subscanMenuOption: () => cy.get('[data-cy=menu-option-subscan]'),
-  transactionList: () => cy.get('[data-cy=container-transaction-list]', { timeout: 20000 }),
-  pendingTransactionItem: () => cy.get('[data-cy=container-pending-tx-item]'),
   reviewButton: () => cy.get('[data-cy=button-review-tx]'),
   setIdentityMenuOption: () => cy.get('[data-cy=menu-option-set-identity]'),
 
@@ -17,5 +15,12 @@ export const multisigPage = {
   thresholdListItem: () => cy.get('[data-cy=list-item-threshold]'),
   balanceListItem: () => cy.get('[data-cy=list-item-balance]'),
   signatoriesAccordion: () => cy.get('[data-cy=accordion-signatories]'),
-  expandSignatoriesIcon: () => cy.get('[data-cy=icon-expand-signatories-summary]')
+  expandSignatoriesIcon: () => cy.get('[data-cy=icon-expand-signatories-summary]'),
+
+  // transaction list elements
+  transactionList: () => cy.get('[data-cy=container-transaction-list]', { timeout: 20000 }),
+  pendingTransactionItem: () => cy.get('[data-cy=container-pending-tx-item]'),
+  pendingTransactionCallName: () => cy.get('[data-cy=label-call-name]'),
+  unknownCallIcon: () => cy.get('[data-cy=icon-unknown-call]'),
+  unknownCallAlert: () => cy.get('[data-cy=alert-no-call-data]')
 }
diff --git a/packages/ui/cypress/tests/unknown-transaction.cy.ts b/packages/ui/cypress/tests/unknown-transaction.cy.ts
new file mode 100644
index 00000000..948bac8f
--- /dev/null
+++ b/packages/ui/cypress/tests/unknown-transaction.cy.ts
@@ -0,0 +1,59 @@
+import { testAccounts } from '../fixtures/testAccounts'
+import { landingPageUrl } from '../fixtures/landingData'
+import { multisigPage } from '../support/page-objects/multisigPage'
+import { txSigningModal } from '../support/page-objects/modals/txSigningModal'
+import { knownMultisigs } from '../fixtures/knownMultisigs'
+
+describe('Unknown Transaction', () => {
+  beforeEach(() => {
+    cy.setupAndVisit({
+      url: landingPageUrl,
+      extensionConnectionAllowed: true,
+      injectExtensionWithAccounts: [testAccounts['Signatory 2 Of Multisig With Unknown Tx']]
+    })
+  })
+
+  it('can see an unknown transaction displayed in the transaction list', () => {
+    multisigPage
+      .transactionList()
+      .should('be.visible')
+      .within(() => {
+        multisigPage.pendingTransactionItem().should('have.length', 1)
+        multisigPage.pendingTransactionItem().within(() => {
+          multisigPage.pendingTransactionCallName().should('contain.text', 'Unknown call')
+          multisigPage.unknownCallIcon().should('be.visible')
+          multisigPage.unknownCallAlert().should('be.visible')
+        })
+      })
+  })
+
+  it('can see the expected state of an unknown tx without call data', () => {
+    const { hashOfUknownCall: expectedCallHash, callData } =
+      knownMultisigs['multisig-with-unknown-transaction']
+
+    multisigPage
+      .transactionList()
+      .should('be.visible')
+      .within(() => {
+        multisigPage.pendingTransactionItem().within(() => {
+          multisigPage.reviewButton().click()
+        })
+      })
+    txSigningModal
+      .body()
+      .should('be.visible')
+      .within(() => {
+        txSigningModal.callHashLabel().should('contain.text', expectedCallHash)
+        txSigningModal.approveButton().should('not.be.enabled')
+        txSigningModal.rejectButton().should('not.exist')
+        // now provide call data and ensure we see the call info and approve button enabled
+        txSigningModal.callDataInput().type(callData)
+        txSigningModal
+          .callInfoContainer()
+          .should('be.visible')
+          .should('contain.text', 'system.remark')
+          .should('contain.text', 'remark: Unknown Transaction Test')
+        txSigningModal.approveButton().should('be.enabled')
+      })
+  })
+})
diff --git a/packages/ui/src/components/CallInfo.tsx b/packages/ui/src/components/CallInfo.tsx
index eb3c8aa0..2cfa7047 100644
--- a/packages/ui/src/components/CallInfo.tsx
+++ b/packages/ui/src/components/CallInfo.tsx
@@ -200,8 +200,14 @@ const CallInfo = ({
   const hasArgs = useMemo(() => args && Object.keys(args).length > 0, [args])
 
   return (
-    <div className={className}>
-      <CallNameStyled className="callName">
+    <div
+      className={className}
+      data-cy="container-call-info"
+    >
+      <CallNameStyled
+        className="callName"
+        data-cy="label-call-name"
+      >
         {name}
         {!!aggregatedData.callData && withLink && (
           <Linkstyled
@@ -217,6 +223,7 @@ const CallInfo = ({
           className={className}
           severity="info"
           variant="outlined"
+          data-cy="alert-no-call-data"
         >
           No Call data found on-chain. Use Multix to initiate multisig transactions and avoid this
           annoyance.
diff --git a/packages/ui/src/components/Transactions/Transaction.tsx b/packages/ui/src/components/Transactions/Transaction.tsx
index e6f16f8a..d4424560 100644
--- a/packages/ui/src/components/Transactions/Transaction.tsx
+++ b/packages/ui/src/components/Transactions/Transaction.tsx
@@ -58,6 +58,7 @@ const Transaction = ({
           <QuestionMarkIcon
             size={112}
             className="callIcon"
+            data-cy="icon-unknown-call"
           />
         ) : (
           <GestureIcon
diff --git a/packages/ui/src/components/modals/ProposalSigning.tsx b/packages/ui/src/components/modals/ProposalSigning.tsx
index d4ba43ff..e90f1e89 100644
--- a/packages/ui/src/components/modals/ProposalSigning.tsx
+++ b/packages/ui/src/components/modals/ProposalSigning.tsx
@@ -259,6 +259,7 @@ const ProposalSigning = ({
       maxWidth={'md'}
       open
       className={className}
+      data-cy="modal-tx-signing"
     >
       <ModalCloseButton onClose={onClose} />
       <DialogTitle>Transaction signing</DialogTitle>
@@ -298,7 +299,12 @@ const ProposalSigning = ({
             >
               <span className="title">Call hash</span>
               <br />
-              <span className="hash">{proposalData.hash}</span>
+              <span
+                className="hash"
+                data-cy="label-call-hash"
+              >
+                {proposalData.hash}
+              </span>
             </HashGridStyled>
           </>
           {!isProposerSelected && !proposalData.callData && (
@@ -319,6 +325,7 @@ const ProposalSigning = ({
                   onChange={onAddedCallDataChange}
                   value={addedCallData || ''}
                   fullWidth
+                  data-cy="input-call-data"
                 />
               </Grid>
               <Grid
@@ -383,6 +390,7 @@ const ProposalSigning = ({
                 variant="primary"
                 onClick={() => onSign(false)}
                 disabled={isSubmitting}
+                data-cy="button-reject-tx"
               >
                 Reject
               </Button>
@@ -392,6 +400,7 @@ const ProposalSigning = ({
                 variant="primary"
                 onClick={() => onSign(true)}
                 disabled={!!errorMessage || isSubmitting || (mustSubmitCallData && !callInfo?.call)}
+                data-cy="button-approve-tx"
               >
                 Approve
               </Button>