Bristol, Birmingham and Manchester have topped the list of regional cities most popular with law firms looking to set up centres outside London where they can save around a fifth on their office costs.

In a report published today by global real estate advisor CBRE, Bristol, Birmingham and Manchester topped the list of cities that law firms have set up centres in.

The total space occupied by legal services businesses in Bristol amounts to 874,321 sqft, which includes DAC Beachcroft and Simmons and Simmons offices.

Hogan Lovells, Eversheds and DLA Piper make up some of the 781,893 sqft of legal services offices in Birmingham, while Manchester currently has 774,922 sqft of office space dedicated to low cost legal centres.

A separate report by Jomati Consultants, found that firms save up to 22% off the cost of their office space by setting up offices in the regions.

It found that savings that have been made by firms including Ashurst, Freshfields Bruckhaus Deringer and Latham & Watkins on office rent in regional centres reached £7 per square foot (sqft).

The report compared the advertised rate and the price paid for offices per sqft to the prime market rate for City real estate as listed in the first half 2015.

For example, Berwin Leighton Paisner (BLP) operates a centre at 76 King Street in Manchester which takes up 8,900sqft. The estimated cost per sqft of that office is between £25 and £30, compared to £32 per sqft in the City.

Latham & Watkins also set up a centre in Manchester which takes up 6,055 sqft of space at 1 Marsden Street, which costs an estimated £27 per sqft compared to £32 in the City.

The report shows that firms prioritise striking a balance between location and availability of local talent when choosing where to set up low cost centres. It states that financial, personnel and accessibility considerations appear to be the "big three" drivers of firms establishing low cost centres.

Other considerations raised by individual firms that took part in the report included data protection, local employment laws and IT latency (the amount of time it takes data to travel from one location to another).

The report also depicts the type of state support provided to firms who have chosen to set up centres in regional areas.

In 2011 Allen & Overy was provided with £2.5m of state-backed assistance to fund up to 300 jobs at its Belfast-based centre, while Ashurst received £2.4m to part-finance the further expansion of its Glasgow office.