In order for the contract of employment to remain enforceable, yes.
No obviously the main part of the contract (i.e. going to work) is coming to an end anyway, so you wouldn't lose out much on that front. But there are other parts of the contract which you would lose out on, such as payment for holidays you have accrued but not taken*.
Also any benefits which might have a run on period, like private healthcare, or any other perks that remain after leaving.
Basically if you don't give notice you have breached your contract and have no right to receive any of the benefits of it**.
(*Anything above the statutory minimum, anyway)
(**except for payment for the work you have done up to the point you bugger off)
▪
┌────┐ ┌────┐
│ │ │ │ ▪
│ └────┘ │
│ ──┐ ┌── │ ▪
┌──────┤ ▪ ▪ │
┌┘ │ │ ▪
┌─┤ └──┐ │ │ ┌──┘
│ │ │ ││ ││ │ ┌─┐
│ │ └─┼┤ └┴─┴───┘ │
│ │ ─┘│ │
│ │ ┌──────┐ └┬──────────┘
│ │ │ │
│ │ │ │
└───┘ └───┘ |
