Theresa May is reportedly "distinctly unimpressed" by attempts by Liam Fox to secure a transfer of powers and personnel from the Foreign Office to his newly formed Department of International Trade.
In a leaked letter to foreign secretary Boris Johnson, Fox called for a "rational restructuring" which would see the FCO's economic diplomacy team move over to the Trade department.
The Times quoted government sources calling the letter an "institutional insult and assault" to Johnson's team.
MPs may struggle to hold Brexit department to account, warns think tank
Treasury eyes new financial services director general to oversee Brexit shake-up
Theresa May orders clampdown on Whitehall's special advisers
Downing Street sources told the same paper that the prime minister believes "there is a big job to do and people need to get on with it", rather than engaging in a turf war.
It is understood that Johnson roundly rejected his colleague's suggestions, only offering to send a few staff to the new department on a temporary basis.
There have also been suggestions of a delay to the Brexit process, with The Sunday Times reporting yesterday that neither Fox's department nor the new Brexit department headed by David Davis will be ready in time to trigger Article 50 in January 2017.