Britain leaving the European Union would only suit Russian president Vladimir Putin, US presidential hopeful Donald Trump and so-called Islamic State, Alastair Campbell has warned.
The former Downing Street spin doctor will tell the Irish Business and Employers Confederation that "no serious overseas player thinks we should leave, unless it suits their agenda."
He adds: "Putin probably. Isis definitely. And, depending what mood he is in, Donald Trump. That's about it on the international scene."
Mr Campbell also claims the referendum is as significant to Britain as several general elections.
Mr Campbell is in Dublin to rally business leaders to mount a campaign to persuade 1.5 million Irish voters in Britain to back staying within the EU.
He is appealing to Irish people to help swing the vote towards remaining within the EU by calling or emailing family, friends and contacts.