Dutch foreign minister Bert Koenders has welcomed Tuesday’s speech by British prime minister Theresa May in which she gave more details of her approach to negotiations on Britain’s withdrawal from the EU.

‘We welcome the outline #Brexit,’ Koenders said on Twitter. ‘NL wants a constructive relationship between the EU and UK.’

The other 27 EU countries are ready to negotiate once notification has taken place, Koenders said. May has said that will happen by the end of March.

However, Dutch business associations on Wednesday warned about the consequences of a hard Brexit on Dutch industry. In a joint statement, they said they ‘regretted’ May’s decision to make a radical break with the EU.

‘If you leave the internal market and the customs union in its current form, we are talking about a hard Brexit, the VNO-NCW and MKB-Nederland said in a statement.

A British withdrawal from the EU will cost the Dutch economy €10bn in lost income by 2030, according to calculations by the government’s macro-economic think tank CPB.

The drop in trade with Britain will mount up to 1.2% of GDP within the next 15 years, the CPB said last summer. The impact of a Brexit on the Netherlands will be larger than in many other countries because of the close trading links.