David Crane of Debatewise wrote a great post about what he got out of Seedcamp over on the Seedcamp blog. It is full of juicy goodness and great to read that David (and others) got a lot out of Seedcamp week. The whole post is worth a read but I wanted to pick out one passage:
The very act of applying [to Seedcamp] was useful because you can’t answer 32 probing questions in a concise and compelling way without thinking very carefully about your business and how you intend to carry through your plans.
The same is true when you write a business plan. It can be a time consuming exercise but the very act of being explicit about your beliefs and assumptions will improve the quality of thought behind them and will help you iterate the areas where your plan can be improved.
In fact for these reasons Zeus, one of my portfolio companies, is going through the discipline of writing a business plan at the moment, even though we are not fundraising.