As an American, it’s amazing to see current issue polling, then see Con + something.
Your two parties have regularly swapped being in power. Generally speaking the most a party needs to wait for the Presidency is eight years, and less on a federal level.
Your state level government is much more comparable to the UK.
Labour were in power for thirteen years, 1997 to 2010. It is worth repeating that this is the longest period of non-Tory rule we have had since 1763.
The Tory Party have dominated politics throughout the entire history of the UK. By my count, since 1801, that gives Tory 122 years, Liberal etc. 53 years, Labour 33 years, wartime and postwar coalitions (in which the Tories were almost always the largest element) 13 years.