As the Smith Commission had its first meeting yesterday to discuss the next stage of devolution to Scotland, the former prime minister said devolving all income tax powers would be “anti-Scottish and anti-British” and ensure no Scot could be chancellor or prime minister.
Labour is the only party to oppose devolving all powers over income tax in the five-party discussions with the Tories, Liberal Democrats, the SNP and Scottish Greens.
But there have been signs the party is willing to shift position. Shadow Scottish secretary Margaret Curran told The Scotsman earlier this week Labour was “open minded” on an income-tax compromise.
In a debate in the House of Commons last night, Mr Brown said devolving income tax, combined with English votes for English laws, would turn Scottish, Welsh and Northern Irish MPs into “second-class citizens”. He also warned the UK had “a constitutional crisis in the making”, which he claimed arose from Prime Minister David Cameron’s statement immediately after the referendum, promising English votes for English laws.
He pointed out that the Scottish Tories’ Strathclyde Commission on devolution, accepted by Mr Cameron before the referendum vote, said the voting rights of Scottish Westminster MPs should not be diminished.
In a message to his party on income tax compromise, Mr Brown said: “This proposal to devolve 100 per cent of income tax and then exclude Scottish MPs from voting on income tax at Westminster is anti-Scottish. Excluding Scots from voting on key matters, makes them second-class citizens in the House.
“It is also anti-British because by abandoning income tax as a shared tax, it threatens to end the pooling and sharing of risks and resources that underpins the unity of the UK.
“And it looks like the Trojan horse for fiscal autonomy, which would split the Union and enable the SNP to get through the back door what they cannot get through the front door.”
Mr Brown said Scots “are and must remain” qualified for the highest offices of prime minister and chancellor, which, he said, would not be the case under the Conservatives’ plan.
He said: “Members opposite might find it appealing that no MP from a Scottish seat could, under such a system, ever again be chancellor or prime minister – although this is closing the stable door 20 years too late.”
In an interview in Tuesday’s Scotsman, Ms Curran hinted that her party was preparing to compromise on the issue.
She said: “I am going into the Smith Commission open-minded about the arguments. We want to be constructive.
“If someone comes to me and says there are some arguments you have got wrong and this might not undercut Scottish resources, I would listen to that.”
But in a sign that positions are hardening, a senior Scottish Labour MP said last night: “Gordon speaks for the overwhelming majority of [us] and basically all of us apart from the Tories and the Nats.
“This [income tax devolution] is a Trojan horse for independence. The underlying message is that the Tories have always been anti-devolution and now they are trying to destroy it again with this proposal.”
However, in signs of a split in Scottish Labour, another senior MP said failing to compromise would be “suicidal”.
Mr Brown used the debate to present a 120,000-signature petition demanding the UK party leaders kept their referendum “vow”. He said he believed there were 16 new powers that could be agreed, including the devolution of attendance allowance, housing benefit and elections conduct.
After the debate, a Downing Street source said: “In the end, this was a back-benchers’ debate and what matters is what Labour say and agree to in the Smith Commission talks.”
Scottish Secretary Alistair Carmichael, a Lib Dem, said any deal “must be consistent with the creation and continuation of a United Kingdom which has the constitutional framework and integrity that will retain a United Kingdom”.
Perth MP Pete Wishart, for the SNP, accused Mr Brown of wanting to be “a one-man Smith Commission”. He said: “His obsession with English votes for English laws is only going to damage the whole process.”