Staff at some of the Netherlands’ biggest DIY chains are being asked to keep an eye out for people buying unusual quantities of goods which could be used in a terrorist attack, the AD said on Monday.

Workers at Gamma and Karwei stores have been given leaflets by their employer telling them what to watch out for, the paper said. The list includes acetone, artificial fertilizer and hydrogen peroxide and includes quantities which should be considered to be suspicious.

Personnel are also urged to look out for people acting nervously, insisting on paying cash for large orders and who don’t seem to understand what a product is normally used for.

In such cases, staff must keep the cash register receipts, security camera footage and note down car registration plates, the AD said.

The instructions to staff follow the introduction of new legislation on June 1 which aims to stop terrorists from buying bomb making equipment in ordinary shops.

The law requires shops to be alert, Eric Jan Schipper of the Intergamma group told the AD. ‘Wholesalers, delivery companies, pharmacies, garden centres – the law applies to every business where at least one potential component of an explosive is for sale,’ he said.

‘This is not about getting at customers,’ he said. ‘This is what the law requires us to do, and government inspectors are checking up on it. We are complying in two ways: we already monitor sales in our computers and are now doing it via staff on the shop floor. And to clarify, it is about behaviour, not appearance.’