Whitehall is not set up in a way to successfully negotiate and implement new global trading relationships, according to a report by the Institute for Government (IfG).
Taking Back Control of Trade Policy suggests that good deals will require civil servants to work across departments and collaborate with businesses, but that this is not the way they normally work.
Instead, it argues that the civil service's standard way of working is secretive, generalist, and unwilling to make difficult trade-offs - all of which are enemies of doing good deals - and that it lacks the necessary expertise.
"Whitehall is not set up to do trade well," IfG brexit programme director, Jill Rutter, said. "Ministers will find that taking back control of trade also means taking back responsibility for some very difficult political choices - and they need to be ready to make and justify them."
A new Department for International Trade was set up on 13 July 2016 after the UK's decision to leave the EU, but the report highlights that stand-alone trade departments are unusual in other countries.
It instead sets out nine ways the UK can become a powerful, independent player in international trade, which are:
The government assemble a small cadre of specialist trade negotiators
Development of a cross-government trade strategy
Ongoing engagement with devolved administrations, businesses, and consumer and environmental groups
Guaranteed direct vote for parliament on future deals before they are ratified
An independent body on trade be set-up
Government recognition that there is more to trade policy than trade deals
Aim to run four or five negotiations at a time
Focus on existing EU free trade agreements, particularly with Canada, Singapore, South Korea, Switzerland and Turkey
Beyond the EU agreements, the UK should start with Australia and New Zealand.
"Trade policy is about much more than making deals. There is a real danger that the UK wastes its limited capacity launching trade negotiations with large numbers of countries, and either doing bad deals quickly, or getting bogged down in protracted talks going nowhere," report author, Oliver Ilott, said.
"The government needs a strategy that targets a few priority countries and explores options that may be better than free trade agreements."