If Alistair Darling wants to balance his books, then perhaps he should have a word with the Defence Secretary. On October 30, Des Browne announced plans to spend £2bn a year on nuclear weapons. Annual expenditure on Britain's weapons of mass destruction has increased by £500m and will rise further if the government goes ahead with its plan to build a new nuclear weapon system to replace Trident.

Gordon Brown and his Chancellor have a clear choice. They can borrow £2.7bn per year to compensate for abandoning the 10p tax band.

This will almost certainly break their fiscal rules in a time of economic uncertainty. Alternatively, they can scrap nuclear weapons and make the world a safer place.

John Ainslie, Coordinator, Scottish Campaign for Nuclear Disarmament, 15 Barrland Street, Glasgow.

It is said that Alistair Darling's embarrassing U-turn on the problem that arose from his abolition of the 10p tax rate will be paid for by a further £2.7bn in government borrowing.

I think not.

In his recent Budget, the Chancellor based his estimate for North Sea oil revenues on an assumed price for oil over the coming year of $83.9 per barrel. It now looks like the average oil price for the coming year will be around $120 per barrel; and at that price the extra value of the oil produced will be around £10bn.

I imagine that the Chancellor knows he will skim off at least 50% of that extra value - ie, in excess of £5bn. So it seems to me that Scotland's North Sea oil is once again being used to bail out a Westminster government.

Nick Dekker, 1 Nairn Way, Cumbernauld.

The similarity between the UK and Scottish Labour leaders is remarkable. Both were installed unopposed. Both were regarded as outstanding politicians. Both subsequently proved incompetent. Both have now forfeited authority over their fellow members of parliament.

Where they differ is in their reaction to current problems.

On the referendum fiasco, hapless Malcolm Chisholm epitomised the party's denial of reality when repeatedly asked on BBC's Newsnight Scotland the simple question: "Do you reserve the right to vote against the SNP referendum?"

Logic suggests three possible answers: "yes", "no", or "I decline to answer". Instead, Mr Chisholm used the expression: "We're not giving the SNP a blank cheque." Seven times.

Therein lies the major difference between the two leaders. Gordon Brown has acknowledged the blunder over the 10p tax band removal, with remedial measures being taken.

Wendy Alexander, meanwhile, deflects blame on to the SNP, while leaving us all in the dark as to what her exact position is on the subject.

Robert Dow, Ormiston Road, Tranent.

Bill Aitken (Letters, May 14) demonstrates clearly how little the Tories have obtained for cosying up to the SNP government. In fact, the Tories have a history of flip-flop over the future constitutional shape of the United Kingdom that almost rivals that of Wendy Alexander - albeit over a longer time.

Back in 1968, Tory leader Edward Heath committed the Conservatives to a Scottish Assembly in the long-forgotten Declaration of Perth. The committee he appointed under Sir Alec Douglas-Home recommended a Scottish Assembly of 125 members. In 1979, Sir Alec urged voters to vote "no" to the Labour government's proposals on the basis that the Tories would produce a better bill.

The came Margaret Thatcher, whose opposition to a Scottish Parliament and her general anti-Scottish policies and attitudes blew away the Conservative representation in Scotland, and severely fractured the unity of the UK.

In 1997, the Tories campaigned against the whole idea of a Scottish Parliament, although, paradoxically, the proportional system of election rescued them from oblivion. After 1999, they executed a not-too-elegant volte face again to become supporters of the parliament. Since 2007, they have given succour and support to the SNP government. A wondrous and curious thing to behold is Tory support for the Union.

By my count that is six Conservative positions since 1967 - admittedly fewer than Ms Alexander's seven positions since a week last Friday, but not exactly a model of clarity, either.

Scottish Liberal Democrats, on the other hand, have consistently supported home rule for Scotland within the United Kingdom, recognising that this best served our country's interests. As commentators have pointed out, we gave up the opportunity to be in government because of our opposition to Scotland separating from the rest of the UK.

Robert Brown, Liberal Democrat MSP for Glasgow, 142 Queen Street, Glasgow.

All members' wives are equal, but some members' wives are more equal than others. Mr Speaker and spouse are out of touch, out of line and definitely out of "Order! Order!"

Ruth Marr, 99 Grampian Road, Stirling.