What difference a vote makes

Is the Scottish voting system a model for the rest of the UK?

The latest BBC Parliament documentary investigates how we choose our politicians.

Alicia McCarthy talks to politicians at the heart of the PR debate and looks in detail at the present and possible future electoral systems across the UK.

'Power in Proportion' considers the impact of the new assemblies' electoral systems, and asks whether Britain has got "PR creep".

Proportional representation is the electoral system of choice for new political institutions in the UK.

The Scottish Parliament, Welsh Assembly and London Assembly are all elected by PR - a system which allocates seats to parties on the basis of the proportion of votes they receive.

Westminster, for now, is sticking to its traditional system of 'first past the post', where the candidate with the most votes in each constituency wins, no matter how small the majority.

Alicia visits one constituency - Romford - which changed hands at the last Westminster election, and talks to its Conservative MP Andrew Rosindell.

He says the first past the post system ensures that there's a close link between MP and constituents.

Back to the roots

But Labour MP Martin Linton says change is needed. He argues that the present system disenfranchises, for example, Labour voters in the South West who have little chance of electing an MP from their own party.

In 1998 an independent commission led by Lord Jenkins recommended electoral reform for Westminster but the plans were put on the back burner.

However, the Government says it will look again at electoral reform in the light of the experience of PR in Scotland and Wales.

In Scotland, after more than four years of devolution to the Scottish Parliament, politicians are looking at the prospects for PR in local government.

Liberal Democrat MSP Iain Smith says PR nationally has been a success. Scottish Socialist MSP Frances Curran - whose party is one of the big winners - says it¿s moved the political landscape decisively to the left.

But others are less sure of the benefits. Labour backbencher Elaine Smith MSP is concerned that PR is being used as a substitute for parties properly reconnecting with voters at the grass roots.

Power in Proportion is broadcast this Sunday, 30 November, at 1530 GMT.