3. BT - £600m

After a channel shopping spree in the noughties, the UK’s largest carrier has a sizeable VAR operation that it has striven in recent years to make less fragmented.

The major move to this end came last year when the BT Engage IT, dabs and Business Direct divisions were effectively merged, although a unified brand is yet to be unveiled. Working alongside the newly joined trio is Cisco partner BT i-Net. All four still file separate trading accounts and each is a £100m-plus operation.