offered job and then taken back offer??

Company reneging on job offer?! rights??
I was recently offered a position at a local company. I recieved a letter offering me the position and telling me my start date etc...
I am due to start monday the 4th and on thursday the 31st july i recieved a call from one of the directors saying that they no longer wished to take on any staff and basically that it is tough. I have come off benifits an filled in all forms (working familys etc...) as well as paying nearly £300 for childcare. Which they knew i had done. i had also had my P46 from them and theyre PAYE number etc... do i have any rights??