Thousands of tickets for open-air Masses during Pope Benedict XVI's visit to Britain this week are yet to be sold just days before he is due to arrive.

The Pope starts his visit in Scotland on Thursday. The largest organised event is an open-air Mass at Bellahouston Park in Glasgow on the opening day of his four-day trip to the UK.

The capacity has been reduced to 80,000 after a slow take-up of tickets.

Dioceses in England and Wales have also reported thousands of unfilled places for a London vigil in Hyde Park on Saturday and the service to beatify Cardinal Newman in Birmingham on Sunday.

Officials have blamed the early start, with pilgrims having to leave home at 2am in order to board official coaches heading to the venue, rather than the cost of tickets.

The Roman Catholic Church of England and Wales remains confident that the first-ever state papal visit to Britain will prove a success.