Nous

Why 4: it watches contracts, switches deals, cancels subscriptions and books repairs within permissions you set; how much it does without asking varies by household, so not a clear 5.

What it does. You talk to Nous over WhatsApp and give it your bills and logins. It watches contracts and renewals, moves households to cheaper energy, broadband, mobile and car insurance deals, cancels unwanted subscriptions, fills in forms and books repairs, working within permissions you set. It says almost 250,000 UK homes use it, and it is registered with the FCA, which lets it handle regulated products such as insurance.

Where it falls short. Its headline saving, £734 for a typical household, is the company's own figure. It uses fixed rules rather than its language models for money decisions, which it says reduces errors; how much it does without asking depends on the permissions each household gives it.