The BBC's Reevel Alderson: Scotland has the highest rate of teenage pregnancy in Europe

About 50 members of the Pro-Life Alliance demonstrated outside the St Enoch branch of the store in Glasgow, where the clinic opened on Thursday.

The clinic is a joint venture between Boots and the Greater Glasgow Community and Mental Health NHS Trust.

The move was part of a nationwide targeting of Boots stores by campaigners although only one store is offering the service.

Campaigners do not want the pill on the high street

A Catholic church newspaper called for a boycott of the chain store after hearing of plans to issue contraceptives at a drop-in clinic for young people with no age limit or need for parental consent.

Campaigners at the Glasgow Boots held banners and handed out leaflets calling for people to write to the Boots chairman, Lord Blyth, in protest.

Lord Blyth: Likely to receive letters of protest

The chairman of the Pro-Life Alliance, Michael Willis, said his group objected to contraceptives being sold to young people on the high street.

"We know the Family Planning Association provides the same service elsewhere, but we don't want it on the High Street."

Mr Willis, who is 48 and has four daughters and a son, added: "We have got a right to our opinion, and we represent a sizeable minority. I reckon about 8% to 10% of the population share our views."

Mr Willis, who is also a Catholic, argued making contraceptives more readily available would increase the abortion rate.

The campaigners had originally planned a two-hour demonstration but cut their protest short after being outnumbered by Socialist Workers Party members who came to support the clinic.

An SWP member, Mark Brown, said: "I don't think they could deal with the fact that most of the public is pro-choice. We came along today because we felt that these people should not be allowed to try to close down a family planning clinic without any kind of protest.

"We're delighted that they have cut the picket short," he added.

Aim to cut teen pregnancy

Greater Glasgow Health Board, which is running the clinic, said it was not put off by the anti-abortion campaigners because there was a need for the service.

The head of corporate affairs at the health board, Shelagh McKinlay, said the idea was not only to cut the number of pregnancies but also to curb teenage sexual activity.

Dr Susan Carr: "It's a confidential service"

"Research shows that if you provide young people with information, advice and support, not only do they not get pregnant, they also don't start to have sex until a lot later on," said Ms McKinlay.

"So we feel it is doing the opposite of what the campaign groups feel."

Dr Tina Mackie, who is in charge of the drop-in-centre, said: "The service we are providing here is exactly the same as you would get in any family planning clinic the length and breadth of the country."

The Society for the Protection of Unborn Children said it would also be distributing leaflets outside Boots stores in England and Wales attacking the clinic.