German Chancellor Angela Merkel is signaling that agreeing on a new head of the European Union's executive will be a lengthy process and warns it would be negligent to freeze out Britain.

Merkel backs former Luxembourg leader Jean-Claude Juncker to head the European Commission, but Britain opposes the veteran advocate of EU integration. Juncker was the candidate of conservatives who finished first in last month's European Parliament elections.

Merkel told German lawmakers Wednesday it is "grossly negligent, actually unacceptable, how easily some talk about it not mattering whether Great Britain agrees or not, even whether Great Britain remains a member of the European Union or not."

She said good decisions in Brussels are rarely rushed and added "we need time, we have it and so I am using it."