LONDON, Aug. 3 (Xinhua) -- British businesses need urgent guidance on how to deal with a no-deal exit from the European Union (EU), a leading business body said on Friday.

Brexit negotiations between the British government and the EU have been underway since Britain formally said it was leaving the trading bloc in March last year, and it is set to leave at the end of March next year.

However, the details of the exit deal have not been agreed, and it is possible that Britain could leave the EU with no deal reached, with a result of higher costs for importers and exporters as they deal with new tariffs and restrictions across a border which has been totally open up until now.

The Institute of Directors (IoD), a leading business body in UK, revealed in a survey published on Friday that half of businesses do not intend to draw up plans, with smaller firms more likely to be in this category.

Almost half of these firms say this is because they will only make adjustments once the future relationship becomes clearer.

"The government has said it is releasing no-deal notices, and for us a no-deal Brexit is a massive step back for trading with the EU," an IoD spokesman told Xinhua.

"A no-deal with no-planning is even worse. So we are calling on the government to press ahead with its guidance and to give firms an idea of where it is going. We want more guidance from the government."

A fifth of companies anticipate drawing up plans, but three quarters of these also say they are waiting for more clarity about the future UK-EU relationship.

Internationally active firms, trading with both the EU and non-EU countries, are further ahead on contingency planning than the average, with 41 percent reporting they have already actively engaged in this area.

Manufacturing firms (31 percent) are much less likely than financial services (59 percent) to say they do not intend to draw up any plans , and very few firms in both groups have started to implement plans (2 percent and 8 percent respectively), according to the survey.

Just over half of firms with a local branch or subsidiary in the EU have started some form of planning, higher even than EU goods or services exporters (44 percent and 43 percent respectively).

The survey found that 10 percent of firms had already shifted operations to the EU from Britain, with another 10 percent considering it and a further 10 percent ready to review it dependent on the result of negotiations.

"We think more firms should have contingency planning for a no-deal Brexit, or at least have a map of where they might be impacted by Brexit, through price changes or through supply changes," the spokesman said.