TL;DR: The government promised it'd add £20bn a year to the NHS budget, and now it's scrambling to find the money.
What it means: They've basically got three options: get it from somewhere else in the current budget, borrow, or raise taxes.
Rumour has it they're going for option 3, but in a targeted way, raising duties (instead of taxes as a whole) on fuel and alcohol. Duties are basically designated taxes on specific products, usually ones the government is trying to discourage people from using as much.
But people say this is the wrong idea. It's raising the cost of fuel for people already facing higher oil prices this year, and because the pound is worth less than usual at the moment, oil from abroad is more expensive to buy.
The government's just not sure what else to do. They don't think raising income tax would be popular, nor do they want to borrow more... nor is there any leeway anywhere else in the budget. Good luck with that one guys.