The U.K. Government’s Brexit department spent almost £1.2 million ($1.5 million) on internal legal advice during the third quarter of its 2018-19 financial year.

The Department for Exiting the European Union (DExEU) paid the Government Legal Department (GLD) a fixed fee of £1,191,250 ($1,514,549.29) for the period from October to December 2018. The department’s financial year runs from April 1 to March 30.

The disclosures come amid intense political wrangling over the government’s legal position on the EU Withdrawal Agreement, a summary of which was published Monday.

Senior MPs from six parties have written a joint letter to Commons Speaker John Bercow, asking him to launch proceedings of contempt against the government for failing to publish the “full and final legal advice on the Brexit deal” as ordered by Parliament.

The GLD, a non-ministerial government department, operates outside of any political oversight. The £1.2 million legal spend represents the largest sum paid by DExEU to an external organization during the three-month period, ahead of the £720,000 ($915,000) paid to Boston Consulting Group.

The disclosures also reveal that DExEU paid nearly £40,000 ($51,000) to Interserve Facilities Management on estates and facilities costs during Q3 and more than £74,000 ($94,000) on “travel and subsistence” services from Clarity Travel Management.

The figures have been published as part of the DExEU’s transparency data report, which details any spending in excess of £25,000.

“As we unpick more than 40 years of legal harmonization with the European Union, it is essential to have the best legal advice,” a DExEU spokesperson said. “The government’s internal legal services team has some of the finest lawyers in the country and of course we will make full use of them. But where appropriate, we will continue to draw on the advice and expertise of lawyers from the private sector.”

Law firms providing legal support to the government during the Brexit negotiations have included Slaughter and May, which seconded London corporate partner Mark Horton to DExEU ahead of his retirement earlier this year. And the British newspaper The Times reported in 2016 that two Linklaters partners were also providing their services on secondment.

Last year, DExEU spent £3.7 million ($4.7 million) on legal costs, including more than £1.2 million ($1.5 million) on Brexit-related litigation. Legal costs represented DExEU’s second-most significant area of spending, behind staff costs of £14 million ($17.8 million) for the year ending March 31, 2017.

Litigation costs represented almost a third of the department’s total legal spend during the year, with the bulk going toward litigation costs relating to the high-profile Article 50 legal challenge led by investment manager Gina Miller. The remainder of the litigation costs—£78,000 ($99,000) related to Article 127 litigation, which concerned Britain’s membership of the European Economic Area.