UK private sector companies are not obliged to say when they are tendering. So the only way to find out is by good old fashioned sales methods.
However, pubic sector organisations (eg councils, government and their agencies), public funded bodies (eg housing associations, NHS and quangos) and utilities (ex public) all have to advertise their larger tender contract opportunities.
You can pay a service that will check for suitable opportunities and will alert you. This isn’t too expensive and is a boon for companies that are tendering frequently.
If you are new to tendering and want to assess what’s out there, or if you are tendering less frequently, it’s not hard to do your own searching – and it’s free.
There are many other portals like:
London Tenders Portal for London Councils
South East Business Portal for South East councils
If you know other free ways to find public sector tenders please add them.