(Adds details, context)
By Juliette Jabkhiro and Noemie Olive
CALAIS, France, Nov 28 (Reuters) - France is ready for a serious discussion with Britain on issues relating to illegal migration, but will not be held hostage to London's domestic politics, the country's Interior Minister Gerald Darmanin said.
The two countries are already at loggerheads over post-Brexit trading rules and fishing rights and last week relations soured further after 27 people died trying to cross the Channel.
British Prime Minister Boris Johnson wrote to President Emmanuel Macron setting out five steps the two countries could take to deter migrants from making the perilous journey. One of those - sending illegal migrants back to France - particularly angered Paris.
France responded by cancelling an invitation to British Interior Minister Priti Patel to attend a meeting on Sunday with European counterparts to discuss the issue after Johnson published the letter on Twitter.
"Britain left Europe, but not the World. We need to work seriously on these questions ... without being held hostage by domestic British politics," Darmanin told reporters after meeting his Belgian, German and Dutch counterparts in Calais.
He added that London's tone in private was not the same as in public.
France had been handling the issue of illegal migration to Britain for 25 years and it was now time London woke up, Darmanin said.
"If migrants are coming to Calais, Dunkirk or northern France, it's because they are attracted by England, especially the labour market which means you can work in England without any identification," he said.
"Britain must take its responsibility and limit its economic attractiveness."
Britain needs France's cooperation to curb the flow of migrants escaping war and poverty over the English Channel from Europe, health minister Sajid Javid said on Sunday, defending Johnson's letter.
Little was agreed at Sunday's meeting with his European partners beyond further cooperation between police, but the European Border and Coast Guard Agency agreed to provide a plane from Dec. 1 to monitor France's northern coastline, Darmanin added. (Writing by John Irish; Editing by Raissa Kasolowsky)