I lived in London for 5 years, and went through loads of crappy umbrellas once heavy winds inverted them, hence ruining the arms etc.
The one umbrella that really withstood them all is a Tumi one which I bought. It doesn't have to be Tumi, but it needs a wind flap, which basically makes the umbrella two overlapping layers with a overlapping vent (hard to describe, but you may have seen umbrellas that look like a shingled roof -- a smaller umbrella sitting immediately over a second "tiered" umbrella. It is this flap that opens in heavy wind that allows the umbrella to keep it's structure intact. All other umbrellas regardless of brand are SHIT (including Fulton, Totes, etc mentioned above, of which I replaced many before finding the Tumi). As well, the center shaft is of thicker gauge steel -- you can actually feel its solidity, almost like you could use it as a weapon if needed!
The other insane thing about the Tumi brand is that it is 100% replaced in the event of anything going wrong. I had mine broken twice on the subway as a result of people pushing into me. I walked into various Tumi repair locations or stores (one in Vancouver, the other back in London), and had them completely replaced for free with newer current models, without even showing them a proof of purchase (they know approximately when you bought it as the style changes every 3 years or so).
The umbrella itself was selling for 75 GBP back in London, and I believe $120 CAD in Vancouver, but I found it at an incredible price of $45 at Nordstrom in Seattle. It has been replaced 2x, and I've used it for nearly 5 years.
PS: You also look really cool when everyone else is struggling in the wind and your umbrella opens up the wind bypass flap and everyone stares in wonderment, with people frequently commenting and asking where to buy one.
found it for $80 USD online.