What do you do if you receive a tender with abnormally low price, do you reject them or let them proceed. Don’t reject them automatically!

The contracting authority must ask the bidder, in writing, to explain the relevant calculations/characteristics in detail. You may take into account any explanation given regarding such matters as the economics of the manufacturing process, the technical solutions chosen, favourable conditions relevant to that particular bidder and/or the originality of the bid. If the reason the tender is low is because it does not comply with EU environment/social or labour laws, it must be rejected (see Regulation 56(4)).