[Driver TBA]

Thanks to a quick Google. From here.

Resale price maintenance (supplier controlled prices)
Suppliers may try to impose a resale price to maintain brand positioning or to give resellers attractive profit margins.

Any arrangement between a supplier and a reseller that means the reseller will not advertise, display or sell the goods the supplier supplies below a specified price is illegal.

It is also illegal for a supplier to cut off, or threaten to cut off, supply to a reseller (wholesale or retail) because they have been discounting goods or advertising discounts below prices set by the supplier.

A supplier may recommend an appropriate price for particular goods but may not stop retailers charging or advertising below that price. In most cases, a supplier may specify a maximum price for resale.

Suppliers may withhold supplies of goods to a company that engages in ‘loss leader selling’. That is, purchasing goods with the intention of selling the goods below their cost so that:

the company can promote their business
attract customers who are likely to purchase other goods or services.
This exemption does not apply to genuine clearances, or to when a supplier has agreed to supply goods to a company for the purpose of loss leader selling.