You, the people of Scotland, are engaged in a crucial debate about the future of your country, a debate that you and you alone will decide.

But inevitably the future of the United Kingdom, of which you are a vital part, will be much affected.

Therefore I hope you will allow a voice, if not a vote, to your fellow UK citizens about some of the issues you have to confront.

I also want to tell you why, as a citizen of the United Kingdom who is not a Scot, I have found Scotland and its people an inspiration ever since, as a young woman, I first scrambled up the Trossachs, Ben Ledi, Suilven and the Cuillins.

Let me begin with the issues. These cannot be easily dismissed. The first is the challenges Scotland would face winning the same beneficial terms of European Union membership as it currently enjoys as part of the UK.

The First Minister has repeatedly said that a Scotland outside the United Kingdom would want to be a full member of the EU. I agree with him.

The EU has extended democracy and the rule of law far beyond our shores; has become a magnet of hope to the people of troubled European countries such as Ukraine and Georgia; and, above all, has established in western Europe a zone of peace for the past 60 years. Leaving it would be an act of lunacy.

But the EU has developed its own rules, and expects them to be respected. Among the rules are those regarding membership. Scotland, seeking membership as a separate nation, would have to accept them or, at the very least, negotiate any change in them.

At meetings of the European Council, where the governments of all 28 EU members are represented, two conditions have been laid down for new members in addition to the Copenhagen principles regarding democracy and the rule of law.

The first was that any new members would be obliged to accept the Schengen Agreement, which removes border restrictions on the movement of people and goods within the European Union.

The second is membership of the eurozone, the currency area which uses the euro. The United Kingdom is not a member of either and negotiated an opt-out from both. An independent Scotland would have to either accept these conditions of EU membership, or seek its own opt-out, which would not be easy to obtain.

Among our fellow members, there is growing resistance to any more opt-outs in a single market seeking further integration.

Negotiating terms of membership could also see significant changes to the terms we worked for together throughout the decades: the UK rebate and our clout on the common agricultural and common fisheries policies. So I believe Scotland and the UK as a whole benefit from being part of a Britain which is firmly in Europe. It is that composition which gives us the levers to ensure that more people are in work.

In a brilliant speech to the UK Parliament's two chambers on Wednesday, the German Chancellor Angela Merkel referred again and again to the importance of members of the EU working together, to maximise their influence in a turbulent world where Europe has one-quarter of the world's gross domestic product but only 7% of the planet's population.

Europe, she said, would have to become more competitive and more innovative but also more united if it was to deal with the challenges of climate change and technological transformation, while protecting its own values and advancing the EU objectives of peace, freedom and prosperity.

She is far too wise to intervene in Scotland's decision, but it is hard to believe from this speech that she would welcome the break-up of the United Kingdom.

I know that I am not alone in sharing with Chancellor Merkel the sentiment towards ensuring that Britain - and not least Scotland as part of it - remains in Europe, securing the many millions of jobs these partnerships unlock.

Let me turn to another subject that deserves discussion. In his response of February 17 to the speech made by David Cameron on February 7, Mr Salmond referred repeatedly to "the Westminster establishment".

I was interested in what he meant by his use of the term. I assume it was something other than the obvious point that Westminster is the site of the UK Parliament.

After all, Parliament, from Prime Ministers to Cabinet Ministers, officials and MPs' staff, is drawn from all parts of the United Kingdom.

There have been Scottish Prime Ministers, both before and since the Second World War, and many Cabinet Ministers from Scotland, often in senior positions.

So Mr Salmond cannot have been speaking simply of geography. Perhaps he had in mind a group of men (and a few women) who share common values and common objectives.

But that won't quite do either. If I take the most contentious issue in recent British politics, the war on Iraq, I am proud, as the then-Liberal Democrat leader in the House of Lords, of sharing the passionate opposition to it and its disastrous aftermath with three great Scots: our inspiring party leader in the House of Commons, at the time, Charles Kennedy, and his wise successor Sir Menzies Campbell. I honour, too, the then-Foreign Secretary, Robin Cook, one of only two senior Cabinet members to resign (the other was English).

I still remember the rumble of approval from the people who lined the street outside St Giles Cathedral when his funeral cortege passed.

All of us were members of the Westminster Parliament. But could we possibly be described as members of the same establishment? These were voices of conscience but also voices of committed dissent.

Scotland has a global vision. It belongs to the world and must remain part of it. It belongs to Europe and must remain part of it.

I can remember the excitement generated at the one European Council to be held in Scotland in 1992, when the churches and meeting rooms of Edinburgh were opened to a great civic debate on the EU, one in which Jacques Delors, then President of the Commission, took an active part.

From the Edinburgh Festival to the international reputation of Scottish composers and choreographers, great artists and poets, engineers and doctors, missionaries and scholars, Scotland has always moved out from its borders to embrace, and sometimes to transform, the wider world.

I believe a separate Scotland would be a diminished Scotland and would leave behind it a diminished United Kingdom.

And, as Chancellor Merkel made all too clear in her unashamedly pro-European speech, Scotland above all benefits from being in Britain, in Europe and in work.

Shirley Williams, politician and academic, was leader of the Liberal Democrats in the House of Lords from 2001-4.