LONDON (Reuters) - Britain's Theresa May is seeking freedom for businesses to operate within the European Union's single market, her spokeswoman said on Monday when asked what kind of trade deal the prime minister was seeking after leaving the EU.

"I think the PM has said many times that she wants the UK to be the global champion for free trade, that she wants British companies to have the maximum freedom to trade with and operate in the European single market," May's spokeswoman said in response to a question on whether she wanted Britain to stay inside the EU's customs union.

On Sunday, a cabinet minister said Britain had told Nissan <7201.T> it would aim for tariff-free trade with Europe for the motor industry after Brexit, persuading the Japanese company to invest in the country's biggest car plant.

"As you know we are looking very carefully at the moment (at) the different sectoral issues, that's why there is such a level of engagement across government with different sectors," the spokeswoman said.

(Reporting by Elizabeth Piper, writing by William James)