More than 420 jobs are under threat at four HM Revenue and Customs offices in Kent after the tax authority revealed plans to drastically cut back its presence across the UK.

HMRC aims to merge its 170 bases across the country into 13 regional offices and admitted there would be redundancies among its 58,000-strong workforce.

Tax offices in Canterbury (105 staff), Chatham (85 staff), Gravesend (25 staff) and Maidstone (205 staff) are scheduled to close by 2021 at the latest.

It plans to open a regional centre in Croydon and Stratford, which will employ up to 5,300 and 2,800 people respectively.

A specialist centre will remain in Dover, where 145 people work, although it is unclear how many jobs will be needed in future.

The Revenue said the move was part of a 10-year modernisation plan and that many of its offices were in antiquated 1960s and 1970s buildings, with the number of employees ranging from 6,000 to 10.

Chief executive Lin Homer said: “HMRC has too many expensive, isolated and out-dated offices.

“This makes it difficult for us to collaborate, modernise our ways of working, and make the changes we need to transform our service to customers and clamp down further on the minority who try to cheat the system.

“The new regional centres in Stratford and Croydon will bring our staff together in more modern and cost-effective buildings in areas with lower rents.

“They will also make a big contribution to the economy of the region providing high-quality, skilled jobs and supporting the Government’s commitment to a national recovery that benefits all parts of the UK.”

“No one should be in any doubt that, if implemented, these proposals would be absolutely devastating for HMRC and the people who work there..." - Mark Serwotka, Public and Commercial Services union

The Canterbury and Gravesend offices are scheduled to close between 2019 and 2020, while Chatham will shut between 2016 to 2017 and Maidstone in 2020 to 2021.

The Public and Commercial Services (PCS) union said the closure of 160 offices would be “devastating” and called for it to be reviewed by MPs.

Since 2010, more than 10,000 jobs have been cut from the department and 250 offices have closed, plus the network of 281 walk-in tax enquiry centres.

PCS general secretary Mark Serwotka said: “No one should be in any doubt that, if implemented, these proposals would be absolutely devastating for HMRC and the people who work there.

“Closing this many offices would pose a significant threat to the operation of HMRC, its service to the public and the working lives of staff, and the need for parliamentary scrutiny of the plans is undeniable and urgent.”

HMRC raised a record £517 billion for public services last year.