THE SNP policy is for a Scottish state to ratify the new UN Treaty on the Prohibition of Nuclear Weapons (TPNW). Nicola Sturgeon has given strong personal support to this and there will be an SNP observer at the first meeting of the 60 state parties in Vienna in late June.

This treaty requires a firm process and timeline for the removal of all nuclear weapons present in a member state and this will be internationally supervised. What is crucial for an independent Scotland is that the TPNW is ratified before any application for Nato membership ("Nato and EU would be cornerstones of security says Sturgeon", The Herald, May 17). If the Trident issue is not clearly settled, there will be enormous pressure on Scotland to change its position, including a UK veto threat. As with all negotiating positions, once an issue is firmly settled, blackmail pressure becomes pointless.

It should, of course, be emphasised that there is no independent UK nuclear system. There are eight nuclear states which have their own independent systems but the UK is not one of them. The Trident missiles are rented from the United States and have to be returned regularly for servicing. The warheads and submarines are made in the UK but cannot be completed until the US has made its design decisions. The claim that the UK controls targeting has always been met with scepticism by many. This has been considerably strengthened recently by the claims that the Exocet missiles sold by France to Argentina and used in the Falklands war had a "kill-stop" device to keep control of their use in France. That was 40 years ago so how much more sophisticated these devices will be now. It would be irresponsible of the US not to keep control "just in case".

The UK is in the position of a sub-let tenant whose landlord keeps the only key. The rent of course is high. Scotland needs to control its own home.

Isobel Lindsay, Biggar.

* TORY MSP Donald Cameron talks of Nicola Sturgeon “betraying her naivety, and the SNP weakness on international security”. But it’s his own naivety he reveals when he fails to understand that independence would dissolve the present UK, and that if rUK wished to continue as a nuclear power, then the siting of the weapons falls on it.

Has the UK Government held any discussions with the Scottish Government on this issue? If not, why not? I’m sure these weapons could continue at Faslane for a few years, but the subject has to be broached. They could also be moved to France or the United States, if London desired.

I was appalled that BBC Scotland covered none of the First Minister's speech. The snubbing of Ms Sturgeon seems now to be BBC policy, and the reasons behind it should be aired in public, so the licence fee payers can understand.

GR Weir, Ochiltree.

STURGEON CLAIM IS RIDICULOUS

NICOLA Sturgeon has found a sense of humour. Expressing a strong desire for a separate Scotland to join Nato may not meet with unalloyed enthusiasm within the SNP, but it is her policy – along with joining the EU, for membership of which a separate Scotland would not be qualified.

She told an audience in Washington that her "independent" Scotland would play a key role in protecting the world’s seas against Russian aggression. Anyone familiar with the SNP administration’s record in commissioning ferries might well find that hilarious. Not to say ridiculous.

Jill Stephenson, Edinburgh.

THE HIGH COST OF MUTUAL SUPPORT

IT is necessary to look further than Peter A Russell’s observation (Letters, May 17) that there is “a clash of philosophies” between himself and those who have responded to him.

Mr Russell seems to imagine that the words “interdependence and mutual support” are simple concepts, but the difficulty with them is that they depend on the “rules” by which they operate. What is the cost of mutual support? In recent years, this has included, but is by no means limited to, getting a government we didn’t vote for more than half the time, being taken out of the EU when the “Scotland region” clearly voted Remain, the consequences of this, the attempts by the Westminster Government to undermine devolution, and the various attacks on the “less well-off” through such as the "bedroom tax" and Universal Credit.

But at another level "interdependence" means the Scottish economy must operate in the dysfunctional UK economy, one where one or two regions (always London, and often the south-east) forge ahead, sucking in resources that could benefit the rest of the country if only the Prime Minister would do more than intone “levelling up”.

“Interdependence and mutual support” are fine moral concepts, and it is to Mr Russell’s credit that he continues to argue for them within the UK. But I would respectfully suggest to him that he needs to consider whether in practice they really offer Scotland a good deal.

Alasdair Galloway, Dumbarton.

SNP TAKES VOTERS FOR GRANTED

FOR a long time now it has been received wisdom that Labour has lost its importance in Scotland because it "had taken the voters for granted". The re-election of so many SNP councillors shows taking votes for granted after 15 years did that party no harm. The SNP has done nothing to improve education, housing or health, yet is still elected.

My own view is that Labour had many hard-working MPs, MSPs and councillors, but suffered from massive changes in workplaces and the demographics of what "working class" now means. We must remind ourselves that Labour stemmed from the trade union movement, most working class people were in strong unions, and Labour provided a voice for them. For many (particularly younger) workers today not in unions, and on low wages, and working in the "gig" system, the Labour Party is for old men with bunnets, sipping a wee hauf – if they can afford it.

These poor "neo-working class" people have been conned into thinking the SNP actually represents their interests; the SNP only has pie in the sky interests of independence and has now ensured a majority by bringing in Green MSPs who have never even won an election.

J Carr, Glasgow.

A HALF-BAKED BREXIT DEAL

AFTER seven defeats in the House of Commons and illegally proroguing Parliament, the Prime Minister triumphantly announced that he had secured an “oven-ready Brexit deal”.We would inject billions into the NHS and would be free to abolish VAT or set whichever rate we wished. The canny Scots saw behind this nonsense and almost two-thirds of us voted against Brexit.

Now after countless issues with fish farmers, lorry drivers, meat producers and indeed the entire population, it is now abundantly clear that all is not well with the Northern Ireland Protocol ("Hopes of breaking Stormont stalemate over Brexit diminish", The Herald, May 17). This is not helped by the Foreign Secretary announcing that she is going to unilaterally tear up an agreement which was previously agreed in good faith with the EU. Not the wisest way to conduct diplomatic discussions.

Now, I have never seen the Prime Minister’s oven and I have absolutely no desire to view it, but I would suggest that all food coming from it will be half-baked rather like him. Clearly his definition of “oven-ready" differs from the norm.

Stewart Falconer, Alyth.

DEBATE THATCHER IN A CIVILISED WAY

I HAVE no doubt that there are many in the UK who view some of the consequences of Margaret Thatcher’s periods as Prime Minister (1979-1990) with disfavour and have strong views on the subject. That disfavour has been illustrated by the recent treatment of the statue installed in her home town of Grantham, Lincolnshire ("Thatcher statue greeted with eggs and boos", The Herald, May 16). Many of her policies, such as reducing taxes paid by the wealthy, the privatisation of the public utilities, the introduction of the poll tax, and the enactment of legislation restricting trade union powers occasioned much opposition. She did as Prime Minister provide strong leadership and she did lead the Conservatives to three General Election victories.

It is regrettable that the reaction of some to the placing of the statue is to seek to vandalise it and to emit loud noises to express disapproval. The leader of South Kesteven Council has said that it is "appropriate for the debate that surrounds her" to take place where she was born and brought up. Why not let that debate take place in a civilised fashion and establish what the majority of the people of the town desire?

Ian W Thomson, Lenzie.

Read more: We must get out of this unequal Union with its contempt for democracy