What is "British Cinema"?

The Media Students Book, 4th Edition 

In practice, it is difficult to distinguish between "British" and "American" film-making. Consider the Top 20 "UK" films of 2003 as listed by the UK Film Council. The top four films, which took the bulk of the box office, were all American co-productions. 

(more to come)

Slideshare

- A presentation from 2010

<iframe src="//www.slideshare.net/slideshow/embed_code/key/vLxCHh1pSdPowb" width="595" height="485" frameborder="0" marginwidth="0" marginheight="0" scrolling="no" style="border:1px solid #CCC; border-width:1px; margin-bottom:5px; max-width: 100%;" allowfullscreen> </iframe> <div style="margin-bottom:5px"> <strong> <a href="//www.slideshare.net/RSJones/what-defines-a-british-film-13458169" title="What defines a British film?" target="_blank">What defines a British film?</a> </strong> from <strong><a target="_blank" href="https://www.slideshare.net/RSJones">Rachel Jones</a></strong> </div>

BBC

http://www.bbc.com/news/entertainment-arts-26048992

The Guardian

A 1999 article talking about a then-announced definition of a British film (the article won't have looked like this if it was posted online back then, digitisation.

The government's new rules covering the definition of 'British film', (see our News story, 9 July), have come into force today.
There are now two key criteria for a production to qualify as a Brit pic: 70% of a film's budget must be spent in Britain, and 70% of the money allocated to labour must go to either European or Commonwealth citizens. The definition is significant because tax-breaks are available to producers and buyers of officially-recognised British films.
With regard to the revised definition, Films minister Janet Anderson predictably commented: 'our reforms to the definition of 'British film' should make it even more attractive to film in this country'.
The previous ruling had allowed films to be defined as British even if they were largely filmed outside the UK, while debarring films which, though largely British, had non-British soundtracks. One such film was Mark Herman's Little Voice(pictured).
The move comes as recent evidence demonstrates an enthusiasm for 'British film' - official or otherwise - at the overseas box-office. US exit polls for Notting Hill showed that 14% of movie-goers rated 'I like British movies' as a top reason to see the movie.