Two parts to the English question could break the United Kingdom apart and prove fatal for Labour in England.

English voters feel aggrieved, not simply because Scottish voters get their teeth into a disproportionate share of public expenditure, but also because Scottish MPs can vote on exclusively English matters while English MPs are excluded from matters settled by the Scottish parliament.

Alex Salmond wants a referendum on independence, but only in 2010. The first minister plans to move Scotland step-by-step until independence becomes inevitable.

Unless Gordon Brown wrongfoots him by addressing the English question, and by holding a UK-wide referendum before Salmond has the chance to build up a head of steam, the break-up of Britain and indeed of the Labour party looks certain.

For good, sound political reasons Wendy Alexander has called for a referendum now. It is at this point, however, that the political waters begin to get choppy. Alexander believes Salmond would lose an independence vote at the current time. In pushing for an immediate vote, she was seeking pole position for Scottish Labour.

But in doing so she put herself on a public collision course with Brown. For the first time, Labour north and south of the border look as though they will go their separate ways, deeply damaging Brown and fracturing the party.

When the referendum issue was raised by David Cameron, the Conservative leader, on the floor of the House of Commons, Brown seemed unaware, or unwilling to concede, his disagreement with Alexander. But the prime minister’s failure immediately to defend the English interest, as English voters see it, opens up a bridgehead for extremist parties like the British National party (BNP) into Labour’s core working-class vote just as immigration has already done in some areas.

Clearly, it is Westminster MPs, not the Scottish parliament, who must stage the referendum and decide on the key referendum issues, because the future of the union is too important to the people of England, Wales and Northern Ireland to be determined by the Scots alone.

The first key issue is the date when voters can go to the polls. The UK parliament, dominated by Labour MPs, should side with Alexander’s wish for an early referendum rather than allow Brown’s will to prevail in allowing the issue to be pushed into the long grass.

The next issue British MPs must decide is what question or questions should go on the ballot paper. Will there be a simple question asking voters’ views on Scottish independence, or will this be one of a series of questions, including one asking if the Scottish parliament should simply have more powers?

I doubt whether English MPs would settle for such a limited range of options. English voters should be given an equal say on whether the UK is to be broken up, and, if so, on what terms - if a majority of people in the British Isles vote to maintain the union, then the UK government should not enter into negotiations with the Scottish nationalists to tear it up. What it might wish to do is establish a counter-balancing English parliament.

Other issues will keep the English question on the boil. In the autumn, Brown presents a new Queen’s speech. Most of the proposed bills on home affairs will cover England only, or England and Wales. This English legislation will, however, be decided not just by English MPs, but by MPs from Scotland who have their own parliament, and MPs from Wales and Northern Ireland who have their own assemblies.

On English matters, nationalist MPs now rarely vote. But what is going to be the likely effect on English voters if nationalist MPs turn out in full force at the beginning of each debate on English legislation, announce that they should not be participating in the debate, and then walk out of the chamber en masse? Where is that going to leave Scottish Labour MPs who will continue to sit, vote and speak from the government benches?

The English question is also likely to bubble over as soon as parliament has to debate the new round of public expenditure. How are English voters going to react to a slowdown, or a cut in their public expenditure programmes when each Scottish voter gets an additional £1,200 plus each year?

Voters south of the border are becoming aware of how this extra money, paid for by English taxpayers, translates into more generous services — much more favourable personal care of the elderly, a more generous supply of NHS drugs and no top-up fees for university students. These differences have left English voters smarting.

Labour must seize the initiative and lead on the English question by, among other things, setting out the terms of the debate.

The complacent view on Labour benches is that this question will simply go away. Such a laid-back attitude is unlikely to be reflected by English voters, who recognise the reality that the devolution settlement was never properly thought through. This halfway house was never going to work.

Brown should also bring the likes of Charles Clarke and Alan Milburn back into the cabinet. Not simply to assuage the concerns of critics of the so-called “Scottish raj” but because he needs big hitters prepared to challenge him — and in so doing ensure the cabinet is more representative of England with voices that resonate well there.

Frank Field is the Labour MP for Birkenhead and former minister for welfare reform