Although the structure of business plans do vary, they will typically include an overview, a short description of the business idea and opportunity, what makes it different, who will be involved in the business, how you will provide your product or service, your marketing and sales strategy, and financial forecasts that will show the expected profitability.
An executive summary - this is an overview of the business you want to start. It's vital. Many lenders and investors make judgments about your business based on this section of the plan alone.
A short description of the business opportunity - who you are, what you plan to sell or offer, why and to whom.
Your marketing and sales strategy - why you think people will buy what you want to sell and how you plan to sell to them.
Your management team and personnel - your credentials and the people you plan to recruit to work with you.
Your operations - your premises, production facilities, your management information systems and IT.
Financial forecasts - this section translates everything you have said in the previous sections into numbers.
Remember that the person reading the plan may not understand your business and its products, services or processes as well as you do, so try to avoid jargon. It's a good idea to get someone who isn't involved in the business - a friend or family member perhaps - to read this section of your plan and make sure they can understand it.
Video: Writing a business plan
You can find further information on how to construct your business plan on the national GOV.UK website.