Brussels could make the UK wait until March to formally begin post-Brexit trade talks.
The European Commission said today that the bloc must first agree to a negotiating mandate and that can only happen after Britain leaves on January 31.
The EU's timeline is likely to anger and frustrate Boris Johnson who wants trade talks to start quickly and to be concluded by the end of 2020.
European Commission spokesman Eric Mamer was asked today when negotiations are likely to begin and he replied: 'The commission can adopt its proposal for the negotiation directives only once the UK has actually withdrawn from the EU.
But then there is still an institutional process for these to be adopted by the (European) Council.
'This we know will take some time, which is why we have said we will start negotiations as quickly as we can, but it will certainly not be before the end of February, beginning of March.
'This is not a slowing down or speeding up of the process. This is simply the nature of the institutional process and the consultations that need to take place before the negotiation directives can be formally adopted.'
The UK will leave the EU at 11pm on January 31, entering into a standstill transition period until the end of the year.