A MYSTERY intruder who forced pupils to miss a week of crucial classes has cost a school "tens of thousands of pounds".

Life at Crofton School is getting back to normal, more than a week after it was closed following reports a man had set up home in the ceiling cavity.

But bosses at the secondary school in Manwood Road, Brockley, are now angry they will have to fork out to repair damage done to the school building.

They have also paid a private firm to beef up security around the school, in case the fugitive who has not yet been caught returns.

Pupils and staff first suspected someone was lurking in the ceiling before Christmas, when they heard the sound of crawling from above.

Police searched the school's main building on December 30 but no-one was found.

On January 9 fears were once again sparked when associate headteacher Rob Cooper caught sight of a man climbing into the roof.

This time the school was closed on police advice, since when officers have sealed off the main building and conducted a larger scale search, which has involved tearing up large chunks of the ceiling.

An angry Mr Cooper said: "This man has caused considerable disruption to the life of the school.

"A substantial amount of damage has been done to the ceilings. We estimate it will cost us tens of thousands of pounds to repair."

Defending the decision to close the school, he added: "We weren't going to take any risks. The safety of our pupils and staff is absolutely paramount."

Mr Cooper, who expects the school to reopen fully by the end of the week, says security guards will now patrol the grounds of the school for "as long as necessary".

Police say the man was last seen on January 11 but they are confident he is no longer in the building.

Items including a water bottle, drinks cans and an old sock which were discovered by police have now been taken away for forensic examination.

Investigating officer Superintendent Adrian Rabat says they have interviewed a "considerable amount" of people but no arrests have been made.

He also refused to rule out speculation the intruder is a former Crofton pupil.

The man is described as black, around 5ft 8in tall and of slim, athletic build.

Anyone with information should call 020 8297 1212.