Gordon Brown was accused of "stealth campaigning" in the Glenrothes by-election yesterday, after the media learned about an engagement in the constituency only after it had already taken place.

The Prime Minister did not campaign in Glasgow East during the by-election there, claiming that to do so would have breached a convention. The Glenrothes by-election has not been called yet, so Mr Brown's participation in that phoney war was not seen as breaching that convention.

Labour were at pains to insist yesterday that his visit to Glenrothes was in no way a campaigning event. The party's candidate would not be present and Mr Brown was attending in his capacity as chancellor of Adam Smith College.

But although media requests for information about the time and place of the event were rebuffed, photographs were arranged and a press release from the college said the Prime Minister toured the college's Stenton campus in Glenrothes and chatted to creative industries students.

It quoted the premier as saying: "I am delighted to visit Adam Smith College today, to meet the students and staff and to see first hand the excellent facilities and fantastic work that is going on in the area of creative industries. It is also a pleasure to formally launch the Create project which, led by Adam Smith College, is enabling Scottish Colleges to lead the way in Europe with exciting initiatives in eLearning."

Tricia Marwick, SNP MSP for Central Fife, said it was dishonest of Mr Brown to conduct "stealth campaigning" instead of simply going ahead and calling the by-election.

She said: "Gordon Brown should have the courage of his convictions. Instead of pulling the strings from Kirkcaldy and making stealth visits to the constituency he should call the by-election and come and meet the voters of Glenrothes constituency.

"Voters in Glenrothes have seen the difference voting SNP makes with an end to tolls on the Forth and Tay bridges, a freeze in the council tax and investment in new schools and teachers. Gordon Brown should face up to people in Fife and explain why he has taken no action on the rising energy and fuel costs that are hitting families."

But an aide to the Prime Minister said Mr Brown was perfectly entitled, both as chancellor of the college and as a local MP, to conduct the kind of visit he carried out yesterday.