I don't know about across the pond but here in the US we can purchase a product called Airborne.  

The following is their advertisement.  Tired of cold medicines that do not work?  Looking for a effervescent cold remedy that really works? You need Airborne Effervescent health formula. A dietary supplement invented by a 2nd grade school teacher who was tired of catching colds every winter.

My son told me about this wonder drug and it works.  It costs about $6.00 a bottle and I take it when others in the office start with their colds.  It doesn't work against the flu but a flu shot works wonders.

Ddiva