This is a good question, and one I can’t give a definitive answer to!

Some experience of flying is absolutely essential before embarking on your journey to becoming a professional pilot. It gives you examples to draw from in a sponsored scheme or flight school interview, and more importantly, enables you to check you’ll enjoy your dream career before you commit your life and a huge sum of money to flying for a living! I go on about this a lot, but flying light aircraft gives you the chance to enjoy flight in its purest form, and if you don’t enjoy it, you’re unlikely to enjoy airline flying.

Firstly the positives to working towards your PPL before starting your integrated ATPL…

• You dream of a career in flying because you love flying! Working towards your PPL allows you to begin developing your skills and start the learning process early.
• In the initial stages of your flight training at flight school, you’ll find your previous experience may help, freeing up your capacity to learn new things (although not necessarily – see below!).
• The theory exams required for a PPL (there were seven under JAA, but now nine under EASA) give you a lightweight introduction into the style of the ATPL theory exams. This is particularly useful in the initial phase of ATPL groundschool, as you’ll already understand much of the material.
• Some flight schools will allow you to use some of your existing flying hours towards the total required for your integrated course. This means less flying at your chosen flight school, but there is a catch to this (see below).
• If you do your PPL at a local airfield, you’ll get a taste of general aviation in the UK. The big three flight schools do the majority of their training outside the UK, where R/T and procedures can be very different. Flying in the UK and mixing with other GA traffic gives you the chance to mix with other PPLs and develop your airmanship.
• Finally, you never know who you might meet at your local airfield. I know several people who have made contacts at their local airfield which have subsequently led to a job. After my PPL I started flying at Phoenix Flying at Shoreham Airport, which is run by a Senior First Officer at BA. It was him that suggested I apply for the FPP when it opened, so if it wasn’t for him, I wouldn’t fly for a living. On top of that, I now do some instructing for his school and am privileged to call him my friend. None of that would have happened if I’d only flown in Jerez!

And now some negatives…

• Whilst your previous experience might help you through the initial stages of flight training, it can also hinder you! Before I started training at FTE, I flew out of much smaller airfields and often from short grass runways. In situations like this there’s no touchdown zone part-way down the runway – you fly to the numbers! When I started flying in Jerez, the runway was 45m wide and 2300m long, and in order to prepare you for airline flying, we were taught to aim for the touch down zone. Overriding my desire to aim for the start of the runway was difficult at first and used up much of my spare capacity. The same goes for approach technique – doing a PPL you’ll probably be taught to use power to control rate of descent, and attitude to control speed on final approach. This works brilliantly for a light aircraft, but in a jet you tend to use attitude to control your rate of descent, and power to control speed, and so the second technique is often taught at flight school. Both techniques have their uses (and actually a change of attitude will be followed by a power change and vice-versa), but again it wasn’t easy adapting. I’m now able to use both techniques – one when flying at work, and the other flying light aircraft for fun, but during my training at FTE I wouldn’t say my previous experience gave me a significant advantage.
• Whilst I don’t know of a flight school that has a limit for hours flown before enrolling, some sponsored schemes do. Whilst I’m not aware of a hard limit for the BA FPP, the new WizzAir scheme at CTC has a limit of 100 hours, and I think the EasyJet mentored scheme has a limit of around 70 hours (I’m happy to be corrected on this if I’m wrong). The minimum number of hours for a PPL is 45, which is comfortably below any limits I’m aware of. But once you’ve gained your PPL you’ll want to continue flying to keep your skills current, and develop those skills further, so bear this in mind. I remember reading a post on PPRuNe some time ago where a user mentioned they’d stop flying in order to keep their hours down so they could reapply for the FPP. This made me quite sad – I can understand why the limits are there, but it seems a shame to stop doing what you want to do just so you can apply to do the same thing somewhere else!
• Whilst some flight schools will give you a reduction in the hours required for your course, the CAA imposes limits on the maximum amount of credit, which isn’t very much at all. So you’ll do more hours overall, and you can be sure that the hourly refund given to you by your flight school will be less than the one you pay for the rest of your flying!

Just as an aside, things are easier if you’re considering a modular course. A PPL is part of the modular route, after which you can start your ATPL theory whilst hour-building towards your CPL.

So there we go! Not a firm answer but hopefully enough information to enable you to make up your own mind. As always, if you have any questions, ask away!