phd
Send Clowns is (nearly) right - unless you love CAA examinations, you are probably better off going for the ATPLs straight off. The alternative is having to sit the 9 CPL and 9 IR theory examinations, and then the 14 ATPLs at a later date.
However, the ATPL exams are only valid for 3 years (from the final pass) in which time you must obtain a CPL and IR. If you don't get the IR in this time, your ATPL theory lapses and you will have to sit the ATPLs again! (or sit the 9 IR exams and settle for a CPL/IR)