It sounded a bit far-fetched – that the UK wants to set higher standards for its banks than the EU would allow. But these are Cameron’s words in his statement on Monday [from Hansard here]:
To those who say that we were trying to go soft on the banks, nothing could be further from the truth. We have said that we are going to respond positively to the tough measures set out in the Vickers report. There are issues about whether this can be done under current European regulations, so one of the things we wanted was to make sure we could go further than European rules on regulating the banks.
First of all this relates to regular EU law (Directives rather that Regulations actually, but definitely not in the Treaty). So whatever Cameron had or had not negotiated last week will not have impacted this.




This led me to 
The Constitutional Affairs Committee of the European Parliament yesterday backed
EU justice Commissioner (and, very incidentally, Commissioner responsible for communications)