Number 0870 133 4412 is potentially valid
Ofcom records show that numbers starting 0870133 are allocated to COLT Technology Services. Note that due to number portability if an individual number has moved to a different operator this information is not publicly available.
Ofcom's last recorded change for this number range was July 1999.
The correct way to write the telephone number 08701334412 is 0870 133 4412
For more information on tariffs and usage of numbers starting 08 please visit the page on 08 numbers