Man crawls London marathon in six days

A policeman dressed in a gorilla costume has finished the London marathon after six day - having crawled the route on his hands and knees.

A policeman who crawled the London Marathon in a gorilla suit has finished the race after six days. (AAP)

An English policeman wearing a gorilla costume while crawling the London Marathon has finally finished the race, almost a week after starting.

Metropolitan Police officer Tom Harrison, who goes by the name Mr. Gorilla, raised a reported 26,000 pounds ($AU48,000) for the Gorilla Organisation, which is dedicated to conserving gorillas in countries including Rwanda and Uganda.

The 41-year-old Londoner started the 26.2-mile (42.2-kilometer) route last Sunday and crossed the finish line on Saturday.

Harrison slept at friends' houses in the evenings after completing around 10 to 12 hours and eight kilometres per day.

He has swapped between crawling on his hands and knees and up on his hands and feet to save his blistered knees.

He crossed the finish line in central London flanked by his two sons - and beating his chest.