Diners heading out for food in some London boroughs need to think twice, because new research has revealed they are the least hygienic in the country. 

Other dirty dining destinations include Birmingham and Cardiff - while South Derbyshire and Darlington topped the charts for ratings from the Food Standards Agency (FSA). 

Of the London boroughs, Newham and Ealing have the first and second highest proportion of 0, 1 and 2 ratings - and Harrow has the lowest percentage of top scores of 4 and 5. 

Outside London the worst performing areas in England are Hertsmere in Hertfordshire, Birmingham in the West Midlands and Hyndburn in Lancashire, according to the study of FSA business ratings by website LoveMyVouchers. 

Of the 1249 eateries in Birmingham, 4.7 per cent were given the lowest possible rating for hygiene standards. 

South Derbyshire was the council district that performed the best overall - with the highest proportion of restaurants rated good (4) or very good (5), and no restaurants rated 0, 1 or 2. 

Darlington also performed well, with no 1 or 2 ratings, the highest percentage of 5 ratings, and 98.8 per cent of its restaurants and cafes scoring 4 and 5. 

Six out of the ten least hygienic areas were London boroughs. 

High percentages of zero rated restaurants were recorded in Ealing, Enfield and Brent - all London boroughs. 

Newham has the highest percentage of restaurants and cafes rated between 0 and 2 at 29.2 per cent. 

Barking and Dagenham has the lowest percentage of eateries given top marks with just 27.1 per cent out of 177 premises in total. 

Cardiff was one of the worst districts in Wales with 9.7 per cent of its restaurants and cafes having been awarded a rating of 0, 1 or 2. 

Ten districts did not have any 0, 1 or 2 ratings - including South Derbyshire, Christchurch, Melton, and Newcastle-Under-Lyme. 

Northern Ireland is the best place to visit for hygienic cafes and restaurants, with no zero ratings. 

All districts had less than 4 per cent of restaurants and cafes rated as 2 or 1 more than 86 per cent of rated as 4 or 5. 

The best London borough is Sutton, with no zero ratings and just 4 per cent of restaurants and cafes awarded a rating of 2 or less.