I wish the National Theatre a very happy 50th birthday. To me, it is what subsidy is all about. It could have been a staid presenter of the classics of the English stage. Instead it has encouraged new writing and the discovery of non-English work. It has been challenging and experimental.

Given the opportunity not to play safe, the National Theatre has produced many incredible productions that have become huge hits. Who could have predicted the success of a play starring life size puppet horses?  Or the recent stunning production of Frankenstein? It's hard to believe its director Danny Boyle would ever have learnt the skills to put on that unforgettable opening of the London Olympics without a grounding in subsidised theatre.

It is of course a worry when you rely on a subsidy. I’m about to attend my first Board meeting as a trustee of the Theatre Royal in Winchester and I am already concerned about what would happen if our city council were to follow some other local authorities and cut grants to the arts.

It was the opposite case when I worked at The Mayflower. There, the lack of subsidy meant that the programme was inevitably full of known quantities that could be relied on to fill seats – great shows of course (quite a few subsidised in their original productions) but no thrill of discovery or pushing the boundaries.

To those who object to paying to subsidise something that offends them or they would never go to see, I can only say that for every subsidised play I've disliked, there is something else that I've loved that might never have seen the lights of the stage but for a grant. Les Miserables is one of them. War Horse is another.

Small scale work is important too and more under threat than the large scale endeavours. I still remember the stunning impact of Peta Lily’s Beg! 20 years later- and I look forward to her latest at the Theatre Royal Discovery Centre next week. Blue Apple Theatre’s Hamlet last year changed lives both of the participants and the audience. As a trustee of that company, I know just how much we rely on grants.

It is sometimes suggested that independent shops should be subsidised, perhaps with reduced rates or rents. The idea has merit. The big chains would object to this interference in a free market just as the commercial theatres objected to the creation of the National Theatre fifty years ago. Now we can see that the National has enriched the West End with productions, actors and directors.

Small independents fill gaps. Some become large chains. Others provide a testing ground for new products. Think of the Body Shop for example. They also make a city more attractive to visitors and residents. Winchester is enhanced both by its subsidised Theatre Royal and its large number of independent shops.

This blog was written by Paul Lewis, owner of the marketing consultancy The Lewis Experience and online retailer Your Life Your Style, and former Head of Marketing and Operations at The Mayflower Theatre. You can connect with him on Google+ and LinkedIn.