Yeah, they can come enter a premises without a warrant or permission for a number of reasons, including an arrest warrant.
Think about it. Man wanted for a serious crime. Plod isn't going to wait outside until he leaves the property, could be days, weeks or even longer if criminal knows plod are waiting...
Police can't force entry without a warrant Sod. Worries me how few people these days know their rights, no wonder we're losing all our freedoms.
Also you shouldn't be encouraging law breaking, even when it's committed by the police.