A former Labour minister has warned independence is "inevitable" unless the UK adopts a federal system of government.

Lord Foulkes, who served at both Westminster and Holyrood, said unionists must not be complacent about the SNP after it lost seats in this year's general election.

Scottish Labour members backed plans for a federal Britain in February, although the UK party has stopped short of adopting the same policy.

It supports a constitutional convention which would examine how to extend "democracy locally, regionally and nationally, considering the option of a more federalised country."

The ex-MP made the comments during an interview with STV News looking back on two decades since Tony Blair's Labour government published plans in a white paper for a devolved Scottish Parliament.

When asked if Holyrood may one day be an independent parliament, Lord Foulkes replied: "There is a danger we could sit back and say 'OK, we have got nationalism under control' and that is a very great danger because I have seen the Nationalist's surge go up and up, down and then up and then down again.

"It can come back unless we find a United Kingdom solution. A federal solution for the whole of the United Kingdom that sees Scotland, Scottish devolution and Holyrood in the context of a federal United Kingdom.

"Unless we grasp that and do it properly then we will see the Nationalists' resurgence and when that happens next time independence would be inevitable.

"We have to guard against it and not become complacent as we have done unfortunately in the past."

SNP MP Kirsty Blackman said: "For once his lordship is right - denying Scotland more powers to make our own decisions is completely unsustainable. There is no support UK-wide for federalism in any case.

"Labour should get square behind the SNP's plans to stop the UK Government robbing the Scottish Parliament of its existing powers and back more powers for Holyrood to end austerity, boost jobs, create a fair society and grow Scotland's economy."

A Scottish Labour spokesman said: "Our call for a reformed UK is about meeting the demand for change. One message from the independence and EU referendums was that people wanted more control over their lives.

"That's why Labour's plan for a people's constitutional convention and a federal UK will transform where political and economic power will lie in our country.

"We know that together we are stronger when the nations of our United Kingdom work together rather than split apart."