To find the cost of one pencil, we need to divide the total cost of the 8 pencils by the number of pencils.

Here's the calculation:

$\text{Cost of one pencil} = \frac{£3.81}{8}$

$= £0.47625$

Rounding this to the nearest penny:

$\text{Cost of one pencil} = £0.48$

So, the cost of one pencil is £0.48.

Would you like further details or explanations on this problem?

Here are some related questions for further practice:

1. What if Hayley bought 10 pencils for £4.50? How much would each pencil cost?
2. If she bought another 8 pencils with a 10% discount, what would be the new total cost?
3. How much would it cost to buy 20 pencils at the same price per pencil?
4. If the cost per pencil increases by 5%, what would be the new cost of one pencil?
5. How much would it cost to buy 100 pencils?

Tip: When dividing to find the unit price, always ensure to round appropriately based on the context, especially in financial calculations.