Scotland is facing 50 years of constitutional conflict unless it can break free from the "Punch and Judy Show" between the SNP and Conservatives, Gordon Brown will warn.

In a campaign rally in Glasgow ahead of the European elections, the former prime minister will accuse both parties of taking "ever-more hard-line policy stances" on Scottish independence and devolution, while "neglecting" pressing issues such as the economy and the NHS.

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The former Labour leader will join the head of Scottish Labour, Richard Leonard, and the party's European candidates at the architecture and design centre the Lighthouse to urge voters to back Labour.

He is expected to say: "I fear for the future of Scotland unless it can break free from this non-stop, never-ending, constitution-obsessed SNP/Conservative Punch and Judy show.

"Both parties bang on day after day about independence, continuously ratcheting up the decibel levels with their ever-more hard-line policy stances - the SNP for all-out independence, nothing less, that now has become even more extreme with their plans to abandon the British pound and exit the UK customs union and single market - which would not now count as a soft independence, but a hard independence.

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"Meanwhile, the Conservatives increasingly reveal their hand as hostile to devolution - and because in Scotland they can't talk about Europe or about their policy for austerity they talk about nothing else than the constitutional issues.

"Essentially, we have two parties dug-in for a trench warfare that suits both of them because they have nothing positive to offer on any other issues.

"In fact the two parties' total neglect of the issues that really do affect people - our NHS, our schools, our law and order and our economy - can only have disastrous long-term consequences for the Scottish economy and for Scotland's public services."