By John Knox BBC Scotland political reporter

The home secretary in London wants to introduce new trespass laws to Scotland.

Sex education has been on the agenda at the Scottish Parliament

The Scottish Executive wants its sexual health strategy to apply to Catholic schools.

And the Scottish National Party wants Tony Blair to call a general election on 5 May.

At First Minister's Question Time, the SNP's Nicola Sturgeon condemned Jack McConnell for planning to hand over responsibility for new trespass laws in Scotland to Westminster.

"It would be an offence," she said, "simply to be on land owned by the Queen, to walk your dog on the Balmoral Estate. That clearly overturns the will of this parliament".

She reminded MSPs it was just two years ago that the "right to roam" was enshrined in Scots law.

Final say

Mr McConnell said it was mischievous to suggest the home secretary's new law would apply to the whole of the Queen's estates.

It would only apply to the three royal residences in Scotland: Balmoral Castle; nearby Birkhall House and the Palace of Holyroodhouse in Edinburgh.

Moreover, the "Sewel motion" to be put to parliament next week would give Scottish ministers the final say on which areas would be designated for the new trespass law.

The Liberal Democrats, like the SNP, fear that other areas may be "designated" as trespass zones in the future.

Jack McConnell accused Nationalists of mischief-making

They are threatening to vote against the Sewel motion next Wednesday, unless they are reassured.

The Conservatives believe there are too many Sewel motions being pushed through the Scottish Parliament - 56 at the last count.

As David McLetchie put it, "there's more than a hint that they are being used for reasons of political expediency and in an inconsistent manner".

The procedures committee has already begun an inquiry into the issue.

And the first minister did suggest at question time that the whole Devolution Act might need to be reviewed in the future to give more powers to Scottish ministers, rather than having to win them back each time through Sewel motions.

Sewel motions formally pass to Westminster the right to legislate on devolved Scottish matters which are part of a wider UK bill.

Time of devolution

Mr McConnell maintains that on each occasion they have been used it has been a sensible use of parliamentary time and they have given Scottish ministers powers they would otherwise not have.

This week, two other Sewel motions went through the Scottish Parliament unopposed.

One gives Scottish ministers more powers over the railways. The other gives them more powers over how the National Lottery is run.

The SNP's Nicola Sturgeon was not happy about trespass laws

Sewel motions were invented at the time of devolution by John Buttifant Sewel.

He is a man steeped in the intricacy of politics, vice-principal of Aberdeen University, once a Scottish fisheries minister and now a Labour member of the House of Lords.

A clue to the subtlety of Sewel motions is that he lists as one of his hobbies "watching cricket".

The other big talking point at Holyrood has been sex.

On Thursday Health Minister Andy Kerr announced the executive's long awaited sexual health strategy.

The formula is "delay until you're ready but be safe when you're active".

Teenage pregnancies

He announced an extra �5m a year for advice services to make sure teenagers had access to information and professional help when they need it.

But having come under pressure from the Catholic Church, he made it clear that there would be no change to sex education in schools, no issuing of "morning-after" pills and no fast-tracked abortions.

The former health minister Susan Deacon pointed out that the money was half that being allocated per head in England, despite the fact that, at over 9,000 a year, the rate of teenage pregnancy in Scotland is the highest in Western Europe.

On Tuesday, the SNP somehow figured out that the prime minister is to call a general election on 5 May.

The right to roam on Balmoral Estate was a matter of debate

And since it was Burn's Day, and exactly 100 days to go, the SNP leader Alex Salmond felt inspired to call a dramatic press conference in the Dynamic Earth building, across the road from the parliament, to declare his party's election campaign under way.

He highlighted his main themes as better pensions, no more nuclear power, the saving of the six Scottish regiments and no more "illegal" wars like Iraq.

Strictly speaking these are nothing to do with the devolved Scottish Parliament.

But it didn't stop MSPs debating pensions and nuclear power this week. The SNP outlined their non-means-tested Citizen's Pension in a debate on elderly people on Wednesday afternoon.

And on Thursday morning, the Conservatives made it pretty clear they were in favour of building a new nuclear power station in Scotland sooner rather than later.

Executive budget

They said it was the only realistic way of tackling climate change, the subject of a round table discussion on Wednesday morning at the environment committee.

Experts from the environmental organisations, from the universities and big business were called in to suggest ways of how Scotland could cut its greenhouse gas emissions.

The parliament's most important function was duly performed this week. The Scottish Executive's budget for next year, �27bn, was approved by 63 votes to 13 with the SNP abstaining.

The issues had all been decided months ago, around the cabinet table.

Finally, a little house keeping.

We seem to have to do a lot of this at Holyrood.

The National Lottery is the subject of a sewel motion

This week the members of the management committee, the grotesquely named Corporate Body, submitted themselves to a formal question and answer session in the chamber on Wednesday afternoon.

It was a curiously tame affair.

Critics Margo MacDonald and Fergus Ewing were given short shrift by the spokesman for the Corporate Body, Robert Brown, and we soon moved on to the other 10 questions about such interesting matters as cr�che numbers and parliamentary passes.

We learnt this week too that the new Holyrood building is not worth the �430m we paid for it.

It's been insured for just �380m.

And at the other end of the expenses scale, the parliamentary authorities have called in their accountants to check through the travelling expenses of the Liberal Democrat Keith Raffan.

You may remember he resigned earlier this month on health grounds.

But not until he had claimed over �40,000 in back dated mileage.

It appears that one of his claims, to a meeting in Kirkcaldy, was on a day when he was due to be on official business in the Isle of Man.

He says he's now checking through his own records.