If you believe publications such as Flyer and Flight International there is now speculation of a possible pilot shortage in 2 years time. Let's hope so!
Complete and utter rubbish I'm afraid. The flight training industry has been selling the prospect of a 'pilot shortage' for as long as they've been training pilots. I started to seriously consider a flying career back in the late 1990s, and the schools were saying exactly the same thing then. The fact that wannabes want to hear it doesn't make it true. To add to the reality check, count the number of FTO adverts in the back of any flying magazine, then consider the advertising revenue they bring in, then consider whether the magazine might just have a vested interest in perpetuating this myth. When faced with an industry that knows you are itching to part with £60k+, and would love to get their hands on your money, it pays to treat their claims with extreme cynicism.
To get definitive answers to your other questions would require lots of data from the CAA and individual airlines - which you'll never get - but I'll try and give you my thoughts, from the perspective of a UK airline pilot who is not trying to sell you anything:
How many unemployed pilots (ratings current etc and ready to fly) are there in the uk at present?
Very difficult to say with any precision, but probably somewhere between the high hundreds and a couple of thousand. In any case, the exact number is pretty academic – what matters is that there are lots of people chasing their first break in a market where first jobs are practically non-existant.
How many retirements will there be over the next few years?
Fewer than in the last few years. BA recently raised their retirement age from 55 to 60, and as the UK's single biggest employer of pilots, that on its own will have an effect. Long term, retirement age is only likely to increase further. Again, it's fairly academic, because you will always have more wannabes trying to enter the market than people retiring from it. As an example, my airline employs around 700 pilots, and I can think of 4 or 5 who have retired in the last few months. If we were accepting CVs, I can guarantee you we would get more that that number
every day.
How many student pilots are due to graduate over the next few years?
Thousands. Far more than there will ever be jobs for. If you wanted to be really nerdy, you could look up how many light twins each of the commercial schools has, then, assuming that each aircraft operates say four student sorties per day, and each of those students takes around a month to complete the flying part of their IR, you could calculate a figure. It won't be pretty.
What percentage of new FO jobs have been given to MOD students vs INT students? Actual numbers would help here too.
As I've said, you're not going to get this, but here's a ballpark view of the UK's four biggest employers of pilots. BA, when they recruit low hours pilots, will only take integrated candidates, and even then it's only a handful every month (note that having Oxford on your CV is not a ticket into BA). Ryanair couldn't give a toss whether you were integrated or modular, as long as you can pass (and pay for) their type rating course. Easyjet have traditionally sourced their low-houred pilots from CTC, which is actually a modular course, albeit run on a full-time (aka integrated) basis. Given their new found enthusiasm for pay to fly, however, I wouldn't get too excited about your prospects with them. Flybe don't mind whether you're integrated or modular, and if my experience is anything to go by, the mix is roughly 50/50. That's the big four, who between them account for the great majority of low-houred airline opportunities. Personally, I don't think it makes a convincing case for integrated, but if you think it's worth spending double for a better chance of a job, then fill your boots.
As
Pilot Positive says, all the analysis and number crunching is a little academic right now. There are virtually no jobs out there irrespective of your choice of school or training route, and that situation is unlikely to improve for at least the next couple of years. If you are passionate about flying (and why else would you want to be an airline pilot?) then get down to your local flying club and do some PPL training. It's all hours in the logbook, and at least you can be doing something constructive while waiting for the market to improve.