Chief negotiator of the EU Michel Barnier has warned Britain the bloc will not be a pushover when it comes to agreeing a post-Brexit trade deal.

In a speech this week, he said that in order to reach a zero-tariffs, zero-quotas agreement, the condition must be a level playing field.

"Our aim is to conclude an ambitious partnership with the United Kingdom. But we will remain clear-headed," Mr Barnier remarked.

Although Mr Barnier said the EU will be prepared to offer Britain an "exceptional deal", he warned it will not be "business as usual" and pointed out that rules of origin and customs formalities would still apply.

Furthermore, access to EU markets would be subject to "certification and market authorisation and supervision activities".

European Commission president Ursula von der Leyen added that the EU intends to defend its own interests and those of its citizens "to the end" in terms of negotiating a deal.

The comments came after British prime minister Boris Johnson claimed Britain would not need to adhere to EU regulations under a new trade deal.