I'll be interested as to how much any changes thar are envisaged will be predicted to bring in. Given the overall take from inheritance tax, it's not going to be significant in terms of the tax take. I also wonder how much it will actually bring in as there will be very many highly paid tax advisors ready to go to work as soon as any changes are announced.
https://www.bbc.co.uk/news/articles/c8el3z910r9o 
My guess is that they'll reduce the threshold so that more people's estates are paying it. They could also withdraw some of the reliefs like the rule that increases your threshold to £500k if you leave your home to your children or grandchildren.