Or I could buy it from eBay - I see several units there.

But what exactly is this GiffGaff? Are they a virtual operator? If so, which physical network do they use? Are they limited by data volume of speed? Are they brand new and originally microsim cards, or were they manually cut?

I read the Ts&Cs in their site, they do not take any responsibility regarding the cards:
"2.4. All micro SIMs are provided on an "as is" basis, and without warranties of any kind. No warranty, either expressed or implied is given as to the usefulness or safety of micro SIMs, and Microgaff or the Senders accepts no liability for problems, issues or damages regarding the use of micro SIMs."


You probably remember what US President Harry S. Truman said at the time: There are no free lunches...
:-)

GiffGaff is indeed a virtual operator on the O2 network, but is wholly owned by O2. Their reputation is fairly good, although they lack sufficient disaster recovery plans, so if part of their network goes wrong, they have no failover for some components. GiffGaff don't issue micro-SIMs themselves, but some volunteers cut them and issue them unofficially to new customers, albeit with GiffGaff's approval. I think it's a good choice for your needs.

Thank you for the info.

I'm a bit hesitant about SIM cards that have been cut manually. I know that it works, I've used myself while on a trip to Spain (I cut the SIM into a microsim in front of the astounded sales person).
But inasmuch as possible - I prefer an original microsim.

So I'll look in eBay.uk for other providers SIM cards.
It'll probably cost me more than purchasing one on the ground in the UK, but on the other hand it'll save me the hassle of location a store, waiting for it to open, etc etc.

So given this, which provider would you recommend? Again, I'll only be in London and the south.

I'll have my iPad 2, which is pretty data-hungry, so I'll want a good 3G coverage.

Thank you.

As I said before I suggested GiffGaff, O2 may be your best bet.

With regard to coverage, it's worth understanding the frequencies of each network:

• Vodafone - 900, 1800 & 2100
• O2 - 900, 1800 & 2100
• Orange - 1800 & 2100
• T-Mobile - 1800 & 2100
• Three - 2100

Lower frequencies penetrate buildings much better, so Vodafone and O2 have a slight advantage. However, Orange and T-Mobile recently merged and you can now roam between both networks free of charge, meaning you get two networks' coverage as a customer of just one network. Consequently coverage on these two is arguably better now than Vodafone or O2. Avoid Three, which only has 3G coverage; everyone I know on Three complains about coverage and lack of signal.

Thank you again, NFH.

No problem. I agree with you about cutting mini-SIMs to micro-SIM size. I always prefer a proper micro-SIM too. The chip on some mini-SIMs (even recent ones) is larger than a micro-SIM, which doesn't inspire me with confidence either. GiffGaff should just do what operators like AmaySIM do and issue a universal SIM that can be snapped out in the desired size. No network needs to issue separate SIM sizes.

I found this:
Introducing...our new Micro Sims! - The giffgaff community

And I checked - they don't ship abroad.
I could have them ship to my hotel, though, but I have to check whether I can order one of their packages w/o my having the SIM card first.

Interesting - exactly what I said they should do. Try posting a question in their community and ask whether someone can send one of the new SIMs to you in Israel, once they're launched. These guys sound like quite a helpful bunch. For a full SIM weighing 5g, the increased postage cost to Israel is minimal after the Royal Mail's forthcoming price hike.

I just posted there - and have received several replies within seconds...
WOW!
(Am impressed).

Hi Wisniak,

Did you get the SIM finally ? I came from Hong Kong and plan to visit UK next month. I am checking which data SIM is suitable for me.
Thanks,

Jeffrey