Theresa May and Boris Johnson both "failed to defend the civil service when MPs and commentators questioned its impartiality", independent British think tank the Institute for Government (IfG) has revealed in a report.
According to the study, then-Prime Minister Theresa May didn't protect Olly Robbins, her chief Brexit negotiator, when he became a target of political attacks by hardline Brexiteers, who accused him of "freelancing" and peddling a pro-EU line in Brussels.
"The prime minister was notably silent: she offered no support to her key adviser, who was taking personal and professional attacks as a result of her policy decisions", the report said.
Meanwhile, Boris Johnson left Civil Service officials in hot water when suggesting that he would break the Benn Act to withdraw the country from the EU without a deal on 31 October 2019.
"Under the civil service code 33, civil servants cannot help ministers break the law", the report continued.
According to the study, another complaint from the officials was "excessive secrecy on Brexit" with the “over-classification” of documents.
"Secrecy caused a lot of unnecessary stress in the run-up to 29 March 2019, with far too few people having access to vital documents. The concerns were leaks – but throughout this period it was mainly the political teams in departments, not officials working on Brexit readiness or negotiations, that were responsible for leaking", the report said.
The report says that the Civil Service could still be "forced to prepare for the possibility of a no-deal Brexit... and the problems of the last four years will resurface unless lessons are learnt".
