Prince Charles helps Street party

Prince Charles unveils a plaque on the Street

The Prince of Wales has unveiled a plaque on the set of Coronation Street as part of the programme's 40th anniversary celebrations.

The plaque was unveiled on a wall next to the famous Rovers Return pub, but it will eventually be moved to a green room where cast members relax between scenes.

The prince met Street star Jacqueline Pirie, who plays Linda Baldwin, and was due to meet Liz Dawn - who recently received an MBE from the Queen - and Bill Tarmey, who play married couple Vera and Jack Duckworth.

The prince is due to watch final rehearsals for a special hour-long live episode to be broadcast on Friday evening as the culmination of the anniversary, which falls on Saturday.

Prince Charles talks to Street star Jacqueline Pirie

Eighteen years ago the Queen paid a similar visit to the Street, which broadcast its first episode on 9 December 1960.

There have been more than 3,500 characters in the ITV soap since it began, as well as 25 births, 82 deaths and 51 weddings.

The soap began life as a live series but this was replaced in favour of recordings a year later.

Prince Charles is due to meet the show's creator, Tony Warren, and will sign a copy of the script for the live episode which will then be auctioned next week to raise money for the Manchester Christie cancer hospital.

Writers had to make last-minute changes to the script following the stabbing of actor John Savident last week.

Alison Sinclair, a spokeswoman for the soap, said that the cast, who normally film scenes without rehearsal, had welcomed the challenge of the live episode.

She said: "Morale is really high. Everyone has a real sense of being involved in television history."

The cast of its BBC rival, EastEnders, have sent a bouquet to the cast of the Street, wishing them luck for the live transmission.

The storylines for Friday's episode have been kept under wraps, but popular character Vera Duckworth is seen fighting for her life after donating a kidney to her sick grandson.

Residents of the famous street are also battling to save its cobbles from being covered with tarmac.