A paedophile caught with nearly 8,000 indecent pictures and movies of children as young as two has been jailed for 18 months.

Matthew Chapman, of Cambridge Road, North Harrow, amassed the collection over nearly six years. It included 28 images rated by police as grade five - the worst kind of child abuse image.

The deaf 39-year-old, who also suffers from Asperger's syndrome and dysphasia - the inability to speak words that come to mind - was found with more than 7,000 images and films when police first visited his home in August last year.

Officers had come to his house in keeping with a condition given to him as part of a previous conviction for a similar offence in 2002, but when they asked to look on the desk top of his computer, Chapman told them they needed a warrant.

They returned a couple of days later and sent his computer equipment away to be examined.

In April they came back to arrest Chapman, only to find yet more computer hard drives containing further child pornography files.

Despite his persistent offending, John Hunter, defending, said: "Obviously if it was a normal person very little would prevent them from being sent to prison for a very long time.

"But prison is not going to help someone like Mr Chapman or the public. He continues to commit offences because he doesn't understand that what he is doing is wrong.

"For him it's catch 22. Mr Chapman doesn't know what Mr Chapman doesn't know."

Before sentencing Chapman at Harrow Crown Court on Monday however, Judge Ronald Moss refuted this.

He said: "I understand he is severely handicapped, but how does that impact upon the offences he has committed? It doesn't mean he doesn't know what he is doing is wrong.

"Not only was he downloading this after a previous conviction but he continued to do so when he was under investigation.

"He will continue doing this whatever, that's the problem."

Having already spent 195 days in custody, Chapman could be out of prison in less than three months. However, when he does come out, police will have the right to search his house whenever they want, between 6am and 10pm.