Traders add funds (GBP or BTC) to the site and then place orders to buy and sell. Britcoin acts as an escrow. The site charges no trading fees.
Funds are credited after trading immediately to accounts wherein they can be withdrawn off-site.
The source code and artwork is freely available under the GPL3.
You can trade bitcoins for money by entering either how many Bitcoins you want, or how much money you want for the coins. This "order" is then placed into the orderbook, where other users can accept offers and trade Bitcoins and currency smoothly. All the currency rates are handled by Britcoin itself.
A buy order is executed partially or in full when the price bid can be matched against a sell order that is at or below the bid amount.
A sell order is executed partially or in full when the price asked can be matched against a buy order that is at or above the ask amount.
There are no fees incurred when when transferring bitcoins for deposit. Funds are available once confirmed (4 confirms), a process that takes roughly 40 minutes.
GBP bank deposit
You can add funds through their bank account deposit system. The details are available from the sites page.
The exchange charges no fees for a direct bank deposit. Details are available on the exchange's Deposit page. The reference code uniquely identifies your account.
You can withdraw your GBP to a British bank account and can widthdraw your Bitcoins to a Bitcoin Address. The minimum BTC withdrawal is 0.01 BTC.
Bitcoins may be withdrawn at no charge.
GBP bank deposit
Enter your bank details on the withdraw screen and the money should be credited to your account within 1 business day.
Currently the Britcoin API provides market data.