Bealzebubs figures sound correct for his airline, but as he says it varies by airline and unfortunately the salaries I'm aware the majority of CTC cadets are on (at the big orange) are far lower initially.
£1200 a month subsistence (so it's net) for the first 8 months, with zero allowances apart from £20 per non training night stop.
After that, flexicrew wage for the remainder of their first year. £43 per block hour, £150 per standby. Net could be anything from £1800 in a quiet winter month to £4000 in Summer.
Then it's onto the NEC's SO contract for a year, at the moment around £40k. No flight pay.
I'm personally quite positive towards the NEC, but I do believe in getting the truth out there so people can make the best decisions and for the majority the figures aren't as high as Bealzebub posted.