Glenn Vaughan, Chief Executive of the British Chamber of Commerce in Belgium, was outlining the UK businesses' position on Brexit.
In an interview, he addressed various issues, including the losing and winning of different UK business sectors in case of a Brexit and the possible free trade agreements the UK might have to renegotiate, including the one with the EU itself.
Vaughan, whose organisation represents British companies in Belgium, said that Brexit would be "bad" for the UK, EU and business and would mean the UK having to renegotiate a "whole bunch" of trade deals.
This, he cautioned, would involve not only a "lot of time" but also the training up of skilled trade negotiators.
Vaughan, who was speaking to EU Trade Insights, also warned that negotiating trade agreements with the UK would, for some countries, "not be welcome or a priority."
Elsewhere, Brexit was also discussed at a meeting on Tuesday between UK Prime Minister David Cameron and the directors-general of the business federations from Germany, France, Spain and the Netherlands, alongside the UK business body CBI and Business Europe.
Afterwards, the groups all agreed that "EU membership is the bedrock of their collaboration with the UK."
Spokespeople also told journalists that EU membership is "an important factor in the UK maintaining and attracting £377bn worth of investment from these four countries alone."
The IMF has also thrown its full weight behind the 'Remain' campaign, describing any Brexit as a likely cause of regional and global damage.
Further comment came from Lord Leach of Fairford, Chair of the UK-based think tank Open Europe, who said, "The referendum campaign so far has been underwhelming and voters are little better informed about what the future might look like inside or outside the EU. Brexit will not be an economic disaster and it will not be a utopia."
Aside from the economic dimension of the Brexit campaign, British MEP Julie Girling has cast doubt on claims by German deputy Alexander Lambsdorff that the European Parliament would be unlikely back a British renegotiation deal in the event of a 'Yes' vote in the 23 June referendum.
Girling, an ECR group member, told this website, "He is expressing his personal views, he is only one of 751 MEPs. I do not believe that he, or the ALDE group, will jeopardise the UK's continuing membership of the EU if the British people vote to remain on June 23rd."
She added, "I am confident that the vast majority of MEPs will vote to accept the PM's package. I am not so confident that Parliament will be cooperative if a Brexit vote is successful. I do not think it will be an amicable divorce and Parliament will play a part in making it as difficult as possible for the UK to forge a beneficial trade deal."