LONDON, Oct. 14 (Xinhua) -- The former British Brexit Secretary David Davis on Sunday called on cabinet ministers to rebel against the Brexit plan proposed by the prime minister.

In an article in the Sunday Times, Davis urged the ministers to exert their collective authority over the Brexit plan where Prime Minister Theresa May had suggested a temporary arrangement for the country to remain in the customs union.

"This is one of the most fundamental decisions that government has taken in modern times," said Davis who called the plan unacceptable.

The former secretary said he did not believe in the plan.

The article comes ahead of a crucial summit between May and European Union leaders in Brussels this week which is expected to determine whether or not a deal can be struck.

Brexiteers suspect the plan could turn into a permanent situation, restricting Britain's freedom to strike trade deals with other countries.

Davis said the government's negotiating strategy had "fundamental flaws," arising from the "unwise decision in December to accept the EU's language on dealing with the Northern Ireland border."

Davis resigned from his post in July, days after May's Brexit deal was agreed by the cabinet.