My union rep during the TUPE process was rubbish, turned up late if at all. The HR dept from the LA were awful, about 2 years before at a meeting one of them announced that there were 9 technicians but only 7 jobs!
PeteM is right, on day one the new company can get rid of you providing they can put up a good case but TUPE protects your terms and conditions so your length of service counts towards any payoff. How many people do you know have been made redundant by the IT provider after BSF? I had all the concerns and worries about the process as everyone else and even looked for other jobs. The fact is the MSPs have not got loads of staff waiting to move into schools to take all the jobs, what they have got is loads of people in schools already waiting to fill the jobs.
I got TUPE’d last year and to be honest it’s been a good experience for me, OK the job has changed a bit but I’m still enjoying it. Same pay, same holidays plus extra benefits such as BUPA cover.