Why did the UK enter in a bilateral agreement with Germany in 1935?

I understand the rationale, nudging the Germans towards a balanced fleet that would be easier to contend with but I don't get why the UK embarked on this on their own without France and Italy and/or the other powers who were signatories to the naval arms limitation treaties.

And relatedly, how much did this drive the Italian government away from The UK/France and towards Germany?

If anyone could point me in the direction of something to read on the rationale the government had for going it alone rather than including their Stessa front partners (at least) for a treaty that was a direct repudiation of Versailles, I'd appreciate it.