My orange pay as you go sim has deactivated itself in the nine months we have lived in canada (I expected this).
Is there any way to reactivate it before i arrive back in the uk for a visit?
If not, how do I reactivate it when I get home?

If it's the same as Orange france, you can't reactivate it. You'll have to get a new sim (cost 15 euro in France) which will mean losing your old number.

yup to what Novo said . .

I have just had this issue, on my return to the UK I bought a new sim, plan was to use it each year when I am either in the UK or France. The nice chappies in the orange shop said that as long as I use the phone one every six months it will stay active and not wipe the credit.

All I have to do is remember.......

The nice chappies in the Orange shop were lying through their teeth. Unless you load up with the maximum (100 euros in France) the credit will expire in less than six months. It's much much cheaper just to eat the 15 euro SIM once a year.

In UK you just need to use it to keep it active, text yourself from Canada (45p) and you will keep it active. If you do expire sim cards are free in UK.

Will check when I return to the UK, but I am positive that is what he said.....Then again nice chappie might be a muppet!

I only paid £4.95 for the sim, would be so much easier if I did not have to have a new number each year!

Yep... but as we have found to our cost (daughter had over 20 quid on her PAYG mobile but only ever received calls/texts, too lazy to make any) if it's not used, they switch it off and then recycle the number. The only way to make sure you keep the number is to use the phone - both Orange and O2 told me you have to make at least one paid phone call every six months.

So when we're in Canada, I activate the UK sim once a month just to keep it alive.

However, as I have found this past month, PAYG sims are free these days in the UK. You can order them online and all the issuers (Orange, O2, Vodafone, Three etc.) will send them out (takes only a day or two). You need an address (relative?) and they have to be "registered" to someone at that address but it's very straightforward.

I recently ordered a couple of Vodafone sims (because this summer they have the cheapest pan-European call rates, which are basically the same cost for sending a text or making a call from Europe back to the UK as if you were in the UK). One is currently in my NZ cousin's cellphone making its way around continental Europe (they can load up money onto the PAYG online or by buying vouchers or by credit card over the phone).

And by the way I would have exactly the same problem with my Canadian Rogers cellphone... it has to have $100 loaded on every six months for them not to cancel and recycle it.