Angela Merkel has toughened her stance on Britain’s future access to the single market, saying no exceptions can be made after the country leaves the European Union.

The German Chancellor said Britain can only keep full access to the trading bloc by continuing to allow free movement of people.

Ms Merkel’s response follows Theresa May’s announcement on Sunday in which she said Britain would invoke Article 50 by the end of March 2017, triggering the formal negotiations for Britain’s exit of the EU.

Ms May also signalled she is prepared to prioritise immigration controls over single market access.

Britain’s wait before beginning Brexit negotiations has been interpreted in Europe as a “preparation for battle”.

But Ms Merkel said no exception to the EU’s four freedoms, which include free movement of people, goods capital and services, can be made.

Any deviation from these principles would represent “a systematic challenge for the entire European Union”, she said.

In a speech to German exporters on Wednesday, Ms Merkel said Britain can’t have both things.

She stressed that “full access to the single market is coupled, and inseparably linked, to acceptance of the four fundamental freedoms, and they include free movement of people.”

If one country was allowed to choose which elements to adhere to, “you can imagine how all countries will put conditions on free movement with other countries. And that would create an extremely difficult situation.” she said.

France’s finance minister Michel Sapin said the UK’s long wait before triggering Article 50 was a sign the British government was preparing for tough negotiations that could risk a “hard Brexit” not in Britain’s interests.

He told Reuters: “It (Britain) has given itself time to prepare for battle, but it would be best to not consider that there is a battle.”

“A battle is not in Britain’s interest,” he said, adding that the 27 remaining members of the EU could be counted on to defend their interests in negotiations.

He added: “If there is a country that has something to lose from tough negotiations with dire consequences – what’s called ‘hard Brexit’ – it’s Britain.”