This is interesting (from The Register):

A series of emails and phone calls were not sufficient to establish a contract, the Court of Appeal has ruled. The communications did not contain enough information or the formal qualities necessary for a contract to have been made, it said.

Language school the European Language Center (ELC) used to use vacant summer accommodation and teaching space at the University of Plymouth for its courses. The University told ELC in 2005 that it would have less space available in 2006.

ELC later claimed that emails and phone calls in which the University told it that it would have less space available and which contained estimates that it might have 200 beds available constituted a contract to provide that amount of space.

Plymouth County Court ruled that the communications represented a contract, but the Court of Appeal disagreed…

This doesn’t mean that you can’t do contractual business by email, but the four elements needed for a legal contract (at least in England and Wales) must be present. They are, according to their Lordships:

“an unconditional offer, an unconditional acceptance, a consideration and an intention by both parties to create a legally binding relationship.”

Ah, that lovely word: consideration.