The Manufacture and Storage of Explosives Regulations 2005 permit you to keep up to 50 kg (net) of Hazard type 4 fireworks for no longer than 21 days without the need for a registration or a licence, provided that these are not for sale or for use at work . This is intended to assist private individuals and voluntary organisations that wish to organise a larger firework display. (Hazard type 4 fireworks are the types of less powerful fireworks generally sold at retailers - these provisions do not apply to Category 4 fireworks and may not apply to certain more powerful Category 3 fireworks). You can keep up to 100 kg (net) of Hazard type 3 fireworks for no longer than 3 days. If you are in doubt please check with your supplier or with your local licensing authority. Please note that the requirements of the regulations to store the fireworks safely will continue to apply.
Download HSE guidance on storing and selling fireworks safely here.The guidance is intended for retailers but does also contain useful general advice particularly on storing fireworks.