If having data is critical, spend £10-15 on two carriers and odds are at least one will get the job done.

Hi
 

Im going to spend less then a week in London and I was thinking in getting a prepaid Sim Card, just for data, which company would be the best company? Thx

On the question of best coverage, can anyone from Cambridge (UK) comment on the best provider for that region?

For the city centre, or are you planning to go out into the fens / other bits of rural Cambridgeshire?

Three does OK in London and in Cambridgeshire, except some very rural areas. Coverage in the fens can be quite good, out there in flatland the masts can be seen for long distances :)

For prepaid data anywhere not very rural, Three is probably the best deal. £10.49 for 1GB/1 month, £20.49 for 3GB/3 months. I use the latter in my tablet and rarely lack signal when other phones do.

I doubt you can get cheaper than a tenner all in for a week or two data.

You can pick them up at any three store or other general mobile stores (eg Carphone Whorehouse).

Gagravarr & flatlander,

Thanks for your replies. Will spend most time in the city centre. I was intending to take up a Three offer for voice and data. Reasonably priced and, as you confirm, good coverage.