A round trip of some 800 miles to have one's cake and eat it will seem excessive to many people; not to Alex Salmond, however. Politicians crave power and the SNP leader is no different. The extent to which he might be prepared to go to make and influence policy that not only changes people's lives but also the future ordering of the United Kingdom is revealed by The Herald today. Party sources tell this newspaper that Mr Salmond is giving serious thought to remaining an MP at Westminster after the next general election even if he becomes Scotland's First Minister in the wake of May's Holyrood poll.

A round trip of some 800 miles to have one's cake and eat it will seem excessive to many people; not to Alex Salmond, however. Politicians crave power and the SNP leader is no different. The extent to which he might be prepared to go to make and influence policy that not only changes people's lives but also the future ordering of the United Kingdom is revealed by The Herald today. Party sources tell this newspaper that Mr Salmond is giving serious thought to remaining an MP at Westminster after the next general election even if he becomes Scotland's First Minister in the wake of May's Holyrood poll.

If that happened, he would be the leader of the Scottish government in Edinburgh and the SNP at Westminster. The tartanisation of shuttle diplomacy would be complete. Mr Salmond would want to have his cake and eat it in the political sense, of having a more substantial and meaningful platform (power at Holyrood) from which to harass and harry Gordon Brown when he becomes Prime Minister, scoring points for his party in the process.

Also, SNP sources say he would be able to raise policy on reserved matters on behalf of a parliament where, presumably, they would eventually not apply, should a majority of voters opt for independence in a referendum. In addition, it is said that Mr Salmond would be in a stronger position to negotiate Scotland's independence by having a foot in both the Holyrood and Westminster camps. Mr Salmond would also hope that negotiating reserved matters and independence would prove that the SNP was a responsible party fit for government.

That case has to be made first at Holyrood as a plebiscite on independence will not be won without winning the argument on being a credible government. Victory cannot be taken for granted as a sizeable proportion of the electorate says it would vote SNP but does not see independence as a priority. Time would be on Mr Salmond's side to reassure the public about the party's credentials as there would not be a referendum for three or four years, should the SNP win a working majority of seats in May.

That cannot be taken for granted. The prospect of a dual leadership role is confirmation, if any were needed, that Mr Salmond belongs to the glass-half-full school. Contemplating such a scenario runs the risk of a charge of hubris. Would the job of First Minister not be big enough on its own? Mr Salmond has been away from Holyrood so perhaps he cannot know. There is a danger that serving two constituencies would benefit neither.