Firstly, and most importantly, you must find suitable premises. The regulations set out how much space you will need per child, so once you have worked out how many children you want to have you will know the minimum space required.
You can either rent or buy. But if you want to rent, make sure that you have a reasonable lease on the property. It will be very hard – and expensive – to move after only two or three years in a property.
If you don't want to build the nursery from scratch, you could look at modular nurseries. They are significantly cheaper and can be up and running very quickly. But they might not be popular with the local planning authorities – particularly if you are in a green belt area. So before you make any investment, make sure that the local planning department will give approval for them.
Based on a nursery for 25-30 children you should expect a minimum outlay for a modular nursery to be upwards of £80,000. But to build a nursery from scratch the sky is the limit depending on the location and size of the building.
If you are making structural alterations to a building that already exists, you will need to factor in several thousand pounds depending on its current state. The building might also require some work to bring it up to fire safety standards; for example, ensuring that you could evacuate all the children in an emergency. You should also ensure that there is adequate security, for example, extra locks on doors and windows to keep strangers out and children in.
You should also budget at least £8,000 for toys and equipment. This can include anything from books to tricycles, and puzzles to bean bags. And don't forget that with 25 children playing all day long, the equipment will wear out more quickly than normal. Setting aside a regular amount for replacement should help when the bills come in, but you can also save by buying second hand, as long as the equipment comes with a Kitemark, and is thoroughly disinfected before use.