Interesting. Were drivers balloted? If not, is that not illegal action?
No. It appears they have the right to refuse to cross the picket line to a degree though they could be disciplined for breach of contract. This however means that Merseyrail would have to discipline practically all of it's drivers in one go which isn't realistic. They appear to be happy that it's not organised by ASLEF and is simply the drivers showing their support individually rather than collectively otherwise you could have expected legal action by now.