They can applaud his 'conversion' as they put it on issues like the devolution of policing but they know too that if 'standing up for Wales' works for Carwyn Jones as his party's USP, that's not good news for Plaid.
Relations between the central government and Barcelona have long been strained over issues such as devolution, distribution of revenues and local identity, and Montilla did not wish to serve up another pretext for raising tension between Catalonia and the rest of Spain.