The Northern Ireland Office (NIO) spent almost £90,000 on taxi fares for its members of staff in three years, new figures have revealed.
Following Freedom of Information requests by the TaxPayers' Alliance last year, it was revealed that a total of £87,267 was spent by the NIO on the fares, while another £5,877 was spent on heating during the summer in a four-year period.
The research found that since 2014 Government departments at Whitehall spent £15,383,904 on taxis and summer heating.
Darwin Friend, a researcher at the right-wing pressure group, said that those facing the highest tax burden following the coronavirus pandemic will think it is "deeply unfair" that their money will be spent on taxi fares and summer heating.
In 2016/17 the NIO spent £18,981 on taxi fares, before rising to £30,365 in 2017/18. The following year the expenditure increased once again to £37,921.
Meanwhile in 2014 the NIO spent a total of £3,038 in June, July and August on heating.
During the same summer months heating cost £761 in 2015; £129 in 2016; £546 in 2017, and £1,404 in 2018.
The UK Government said NIO staff are required to travel regularly between its offices in Belfast and London.
"They use public transport where possible, with taxis used only where they represent the most cost effective method of transport available," the Government added.
Mr Friend said that when the country emerges from the coronavirus pandemic, it will be vital that the Government gets its "finances in order", focusing funds on front line services and cutting down on "wasteful" Whitehall spending.
"Whitehall ought to get its own house in order and put a stop to these wasteful anti-eco practices as soon as possible," he continued.
Between 2016-17 and 2018-19, £14,590,284 was spent by 11 Government departments on taxis for members of staff.
Among the departments based at Whitehall, the Ministry of Defence spent the most amount of money on taxi fares between 2016/17 and 2018/19 with a total expenditure of £3,498,317.
That figure includes chauffeur-driven car journeys.
Taxi costs at the department more than tripled between 2016-17 and 2018-19.
The Department for Business, Energy and Industrial Strategy also spent a total of £375,668 on summer heating between 2014 and 2018.
Of this, the department spent £195,197 in 2018 alone, which was the joint warmest UK summer on record.