Finding a laptop under £100 can be quite challenging as it’s a very limited budget for purchasing a new laptop. However, you may find some used or refurbished laptops within this price range. Keep in mind that laptops in this price range are likely to have older specifications and may not be suitable for demanding tasks. Here’s a list of laptops that you might consider:

1. Acer Aspire One Cloudbook 11: This compact laptop offers basic functionality and is available at an affordable price.
2. HP Stream 11: It’s a budget-friendly laptop with decent performance and a compact design.
3. Lenovo Ideapad 100S: This lightweight laptop is known for its long battery life and budget-friendly price.
4. Dell Latitude E6220: A business-oriented laptop with a sturdy build and decent performance.
5. Toshiba Satellite C55-B: A budget laptop with a decent display and good overall performance.
6. ASUS Transformer Book T100: A 2-in-1 laptop with a detachable touchscreen, suitable for light tasks.
7. Samsung Chromebook 3: This Chromebook offers a lightweight design and good battery life, ideal for basic web browsing and document editing.
8. Acer Chromebook 14: Another Chromebook option with a larger display and decent performance.
9. Lenovo ThinkPad X131e: A durable laptop with a rugged design, suitable for basic tasks.
10. HP EliteBook 8470p: A used business laptop that offers decent performance and durability.

Please note that availability and prices can vary, and it’s important to thoroughly research the specifications and condition of the laptop before making a purchase. Additionally, consider checking online marketplaces, local classified ads, or refurbished laptop stores for potential options within your budget.