For the much-criticised Scottish Parliament, it was the final ignominy.

Four MSPs yesterday found themselves trapped for 15 minutes in a lift at the new (pounds) 431m Holyrood complex.

Worse still for the building's battered image, one of the MSPs was Margo MacDonald, who for five years has been one of the project's fiercest critics.

Ms MacDonald, and three other parliamentarians - Phil Gallie of the Conservatives, Tommy Sheridan of the SSP, and John Swinburne of the Scottish Senior Citizens' Unity Party - visited the new complex to take part in an internal Holyrood internet broadcast.

Four other people, including John Brown, the former Glasgow council PR chief and brother of Gordon Brown, were in the lift with the MSPs when it rose to the fifth floor but the doors did not open.

Ms MacDonald, independent MSP for Lothians, said someone used a lift handset to raise the alarm and got through to ''somewhere in England''.

However, they were only able to get out when passing parliamentary staff heard the noise and opened the lift door from the outside. ''It was hot and it was a bit worrying,'' Ms MacDonald said. ''We were all glad to get out. ''It was bizarre - but on the other hand, so many other things have happened with this project that this was barely a splash in the bucket.''

''It's a bit of a bad omen given all the problems,'' said Mr Gallie. ''It's hardly a good advert.''