Sorry to be pedantic but there is consideration- the price that was agreed to be paid It doesn’t have to actually change hands for it to be so.
Having said that I don’t think it’s actually illegal ( no law has been broken) but is probably a breach of contract.
P..S I’m not a lawyer just waiting for my Morgan to be built!
You are right it isn’t ‘illegal’, I was being a bit overly dramatic
You are right of course it is a breach of contract
I’ve successfully faught two cases exactly like this where a judge has sided with me as the aggrieved claimant