Oxford has witnessed the biggest increase in traffic congestion in the UK in the past six months, with 31.2% of its main roads clogged with traffic, according to a new report by TomTom.

Oxford has risen from sixth to third place in a nationwide congestion ranking, with an increase of 2.2% since March 2011, ranking with London and Edinburgh.

London is the most traffic-clogged city in the country with 36% of roads significantly more congested during rush hours than at off-peak times, while the congestion rate was 33% in Edinburgh.

Belfast experienced congestion of about 31% in the past six months and was closely followed by Bolton, Southampton and Sheffield, according to the report.

The UK economy will lose an estimated £20bn per year in production due to road congestion.

The report also said that the UK could save around £2.5bn with an estimated reduction of just 5% in travel time for all business travel on the roads.

Out of the top 50, Bedford, Colchester, Newport, York and Chester have all experienced a fall in congestion over the past six months.

Northampton, Warwick and Chesterfield were the least-congested big towns with congestion rates of less than 10%.