Christmas is coming .... the rush on at Rex London.

For retailers, it's a key date in the selling calendar.

Though a bigger one is shaping up.

SOUNDBITE (English) REX LONDON ACCOUNT MANAGER, SCOTT CLARKE, SAYING: "The worst thing that can happen is that no-one agrees and we crash out of the EU with no deal at all in a few months time." March 29 the due date for Britain to leave - with a withdrawal deal, or deal-less.

British business is backing Theresa May's agreement with Brussels - announced last week - but taking precautions just in case.

Among announcements on Tuesday: Electrocomponents is to spend 30 million pound to increase stocks.

AO World is to do the same.

And Compass, the world's biggest catering firms, wants to build inventory and vary its menus.

The Bank of England, meanwhile, is clear about how unpalatable a no-deal would be.

(SOUNDBITE) (English) BANK OF ENGLAND GOVERNOR, MARK CARNEY, SAYING: "This would be a large negative shock to the economy.

No deal, no transition, we should be in no doubt about that." Potentially, Carney added, as damaging as the oil crisis of the 1970s.

(SOUNDBITE) (English) JOACHIM KLEMENT, HEAD OF INVESTMENT RESEARCH, FIDANTE PARTNERS, SAYING: "The Bank of England is incredibly nervous ... Should we head for a hard Brexit, the Bank of England will likely have to rescue short term market disruptions and banks with liquidity injections and potentially rate cuts.

However, the main scenario still remains and a rather smooth exit in which case the economy in the UK warrants additional rate hikes in 2019." It came as little surprise then that Carney and his policymakers are now throwing their weight behind May's deal.

(SOUNDBITE) (English) BANK OF ENGLAND GOVERNOR, MARK CARNEY, SAYING: "We welcome the transition arrangements in the withdrawal agreement ... We also take note of the possibility of extending that transition period." And, he warned, there's a limit to what a central bank could do in the event of a shock happening instead.

The risk of that is, he conceded, still 'uncomfortably high.'