MANCHESTER, England, Oct 1 (Reuters) - Britain is prepared to be "very flexible" to solve the problem of post-Brexit customs checks on the island of Ireland, Prime Minister Boris Johnson said on Tuesday.

"If you can have Northern Ireland as part of a UK customs union, which is plainly essential, then somehow or other you have to solve the problem of customs checks," Johnson told Sky News. "The UK is very, very prepared to be flexible. We don't want to have any kind of checks at all at the border."

Johnson said one solution might be to have a relationship between exporters and importers, with checks at either end.

"That I don’t think will be onerous, it certainly wouldn’t involve infrastructure, but there might be ways to do it." (Reporting by Kylie MacLellan; editing by William James)