The qualification you are looking for when hiring any security company London offers you is their SIA approval. SIA approval gives you peace of mind that this company has been checked out and verified to be safe. If you are worried about hiring a security company that might not be legitimate, ensure they are an SIA-approved contractor.
London has many security firms with SIA approval, but one that we recommend to you is a company called Grosvenor Security. They are very organised, professional, and completely SIA-approved, so you can hire someone unsuitable for your business. It’s an expense, but it will give you extra peace of mind knowing your chosen security partner is legally permitted to provide the service(s) they offer. SIA approval is a non-negotiable when it comes to hiring security.