Slap all kinds of health warnings on this, but – in view of speculation that the Wills and Kate nuptials might work in the coalition's favour – I thought CoffeeHousers might like to see what happened to the the Tory government's poll rating in 1981, around when Prince Charles married Diana. So here's a graph I've put together from Ipsos MORI's figures. The dotted line represents the date of the wedding:
PoliticsHome suggests that the "royal wedding worked wonders for Thatcher" – but, on the basis of the above, I'm not so sure. It's worth nothing, though, that the Tories surged ahead of Labour as soon as the Falklands War flared up in 1982. By June 1982, Thatcher's party were 27 points ahead of their rivals.
P.S. There's a similar picture if you look at Thatcher's personal satisfaction ratings from the time.