Living expenses at university will vary considerably according to your personal circumstances and lifestyle choices. 
Below is a rough guide as to what to expect to spend in London. Estimates cover accommodation, food and travel but exclude tuition fees.
Whilst basic prices for food, personal costs, bills, insurance, etc will be fairly consistent across the UK,  costs relating to accommodation and travel are specific to London and Imperial College. 

Guide to living cost in LondonBudgetingMoney saving
  Rough guide to university spending   What costs are involved  Money saving tips
  Potential additional cost   Keeping track on expenditure  Council tax exemption
 Need to find private accommodation? Start the search here
Summary of the table's contents