Two teenagers have been arrested on suspicion of arson after an old fish and chips shop went up in flames.

The blaze broke out at the former Mariners fish and chips shop on Nunn's Way, Dereham, at about 7.15pm.

When Norfolk Fire and Rescue Service crews arrived, the first floor and roof of the derelict, already fire-damaged building were well alight.

Firefighters from Dereham, Hingham, Sprowston and Earlham wore breathing apparatus and used fire hydrants and hoses to tackle the flames. The fire was brought under control in just under an hour.

A spokesman for the fire service said the fire was believed to have been started deliberately and investigations were being carried out by police.

Norfolk police spokesman said the fire was being treated as arson and two 16-year-olds had been arrested.

He said: 'A 16-year-old boy from Dereham and a 16-year-old girl from Norwich were arrested on suspicion of arson and taken to Wymondham Police Investigation Centre where they are currently being questioned.'

An eyewitness to the fire, Staci Clarke, said she called the fire brigade after she saw smoke when walking past Iceland.

The 24-year-old, who was with six friends at the time and lives in Kings Road, Dereham, said: 'I saw the smoke billowing through the roof and windows, I knew something was wrong and called the fire crews.'

As previously reported, the Mariners fish and chips shop was damaged by a fire which ripped through the Pact animal sanctuary, which is behind the building on Norwich Street, at the end of 2012.

It has been closed ever since and site owner Basil Todd said it would not be reopening due to problems with electrics, water and gas, as well as 'several other issues there'.

The site is part of Mr Todd's ambitious £1m residential and commercial redevelopment plans. Under the plans, which were given the green light by Breckland's planning committee last year, the site will be partly demolished and partly rebuilt, creating space for three shops and four flats.

The entrepreneur, who owns Wensum Valley Golf and Country Club in Taverham and Billingford Lakes, said the redevelopment will create 40 new jobs.

Did you see the fire? Email kate.scotter@archant.co.uk.