It has a somewhat "Can't do" culture to coin a word, opposite to the US "Can do".
Come up with anything innovative, and you tend to get many people saying that it is impossible and discouraging your ideas, I think far more so than in the US, from what I've heard.
Sort of like the typical British self deprecation, if you are confident and think what you are doing is going to succeed, that can come over as immodest and your peers will tend to act to cut you down and put you in your place. And you will probably also agree with them in this, that you have overreached in some way.
Which is also a prime source of humour in our comedy shows.
But despite that, it is also a great place for invention and entrepreneurs. We tend to be good at inventing things. But often not so good at taking them to completion - though of course with many cases of that as well where inventions are taken to completion.
But I think a certain national tendency to kind of hold back, and not put your all into something, and to feel that it is going to fail somehow. I'm not denying our many successes. We do often get things right but perhaps this tendency for holding back and not completing projects happens a little more than it needs to. To hold back in a situation where someone from the US, say, would most likely press on - and miss opportunities.
Just a general tendency. Of course this doesn't mean that every British person with an innovative seeming idea is on to the Next Big Thing :) and just needs to try harder to succeed.