The shadow business secretary, who made a shock exit from the Labour leadership race blaming media intrusion, is warning that the links between politics in the nations that make up the UK have broken.
He will argue that giving more autonomy to the parts of the union is key to holding it together, and Labour should reflect the new reality with a similarly “federal” structure.
The comments, in a speech to the Progressive Policy Institute in Washington DC, contrast with Ed Miliband’s rejection of an English parliament before the election.
Mr Umunna is expected to say: “What we are witnessing - as the psephologist who came closest to predicting the UK result, Professor John Curtis of Strathclyde University, has said - is the end of British electoral politics as we know it.
“He argues that the first break came in the 1970s when the links between Northern Ireland’s politics and the rest of the UK’s were broken; he argues we have just witnessed the second break where Scotland’s politics takes on a different character to that of the rest of UK, powered by issues of national belonging and cultural identity.
“I think we can maintain the union but we should embrace people’s natural desire in our different nations to have more autonomy over their own affairs and give voice to the different cultural identities in the UK, whilst maintaining the benefits that the pooling and sharing of resources across the constituent parts of the UK brings.
“This is why I believe we need a more federal structure for the nations of the UK with a new English Parliament to sit alongside bodies in Scotland, Wales and Northern Ireland.
“With a federal UK structure no nation will feel left out; each nation’s voice can be properly heard whilst maintaining a UK parliament that will be stronger as a result.”