LONDON, Sept. 3 (Xinhua) -- Downing Street hit back Monday after the strongest attack so far on Prime Minister Theresa May's Brexit blueprint by former Foreign Secretary Boris Johnson.

Johnson used his column in the London-based Daily Telegraph to describe the soft-Brexit plan devised by May as a disaster for Britain.

In response, May's official spokesperson at 10 Downing Street insisted the prime minister was providing serious leadership and a serious plan for Britain's departure next March from the European Union.

The spokesperson added that there were no new ideas in Johnson's article to respond to.

Even so most national newspapers in Britain cited the article as showing the rift between May and Johnson, who some political commentators view as a potential challenger to the leadership of the governing Conservative Party.

Johnson resigned as Foreign Secretary in July just days after May unveiled her blueprint after a day-long meeting of her most senior ministers at Chequers, her country retreat.

Johnson said: "In adopting the Chequers proposals, we have gone into battle with the white flag fluttering over our leading tank. We will remain in the EU taxi; but this time locked in the boot, with absolutely no say on the destination. We won't have taken back control, we will have lost control."

Johnson won some support for his attack from former Brexit Secretary who also resigned following the Chequers blueprint.

Davis said: "He's got a point. We have not been tough enough in the negotiations with the Europeans. Chequers gives too much away for nothing much back."

In its rebuke May's official spokesman said: "What we need at this time is serious leadership with a serious plan and that's exactly what the country has with this prime minister and this Brexit plan. She is a serious prime minister and she has put forward serious proposals."

The Guardian newspaper said Monday that No 10's intervention marks an escalation of the feud between the prime minister and her former foreign secretary, which has intensified since his attack on the government's Brexit plans, widely viewed as a renewed push for the top job.

"Johnson used his newspaper column on Monday to accuse some members of the government of deliberately using the Irish border situation to 'stop a proper Brexit', a claim rejected by Whitehall sources," said the Guardian.

The Independent newspaper said the clash marks the renewal of the parliamentary sitting following the summer recess, raising the curtain on what is likely to be a tumultuous few months as MPs battle over Brexit.

The Independent said over the weekend a plot emerged to bring down May's Chequers proposals, with claims dozens of Conservative politicians are ready to vote the plans down, with Johnson said to be on manoeuvres for a leadership bid.

Brexit-supporting Conservative MPs claim May's Chequers plan would keep Britain tied too closely to the EU, because it would involve adopting a "common rule book" for goods and collecting tariffs on behalf of the European Union.

The war of words comes just 24 hours before MPs return to the House of Commons after their summer holiday. MPs are eagerly waiting to hear if the government will announce Tuesday morning whether there will be a ministerial statement in the House of Commons later that day about Brexit.