Download (data coming to you) at up to 1.5Mbps

Upload (data coming from you) at up to 128 Kbps.

The degree to which these maximum speeds are attained depends on the quality of the signal which is influenced by several factors:

The distance you are from the nearest mobile phone base station

Whether there are obstructions between you and the base station

How many other people are connected via the same base station

The speed at which you are travelling

Additionally, the speed of access is greatly influenced by all the usual Internet factors such as the speed of the server you are communicating with and the speed and usage levels of the links that the communication is going over.