A business plan is usually associated with applying for funding from a bank or other organisation. Actually, business plans can be inward or outward facing.
A business plan prepared with a longer term, broader view is also known as a strategic plan. Having a business or strategic plan is important in the early stages as it provides you with a structure and vision for what you are trying to achieve. All too often the early stages can be about chasing orders or funding and the bigger picture can easily be lost.
The business plan prepared at the start would commonly be a 5 year strategic plan. The document would start with a basic amount of detail on the background to your idea and business model to set the context and remind you of your overall concept.
The main body of the plan will then set the short, medium and long term goals for the business. These could be financial (achieve £X turnover), technical (launch X products, develop a solution for X) or operational (manage a client base of X).
You should also consider the business from all angles, how you will achieve these goals and identify any gaps that exist (e.g. the need for specific skills).
The business plan should also include financial projections which provide you with a way of monitoring the performance of the business. Careful review of these can provide you with early warning of progress not meeting your objectives.
The strategic or business plan should be a living breathing document and reviewed and updated regularly to reflect each stage of the business’ life cycle.