I have been really stupid, new car

Look at your contract, and have a look online to see what the opinion is about cancelling a car leasing arrangement. I've just read something that says a private individual does have a cooling-off period in a car-leasing arrangement, but if that's the case, it should be reflected in your contract.

There's no point feeling stupid - what's done is done - if you do end up losing the deposit, look on it as a rather costly lesson. We once got lured into the Honda showroom by an excellent salesman when we were looking for a second hand car, and nearly got persuaded by him into leasing a brand-new Honda, which he managed to make sound completely reasonable and affordable. (It wasn't). It's just best to go nowhere near salespeople if you don't want to buy something!

There’s a cooling off period, just like when you change phone contracts. Don’t back down, don’t let them tell you it can’t be done. It can, go cancel

No there isn't. The fact that there is a cooling off period for phones is irrelevant. That cooling off period is specific to phones, TV services, internet services and mobile phones. It does not apply to other items. If the OP had ordered the car over the phone or online there is a statutory cooling off period. However, she ordered it face to face in the dealers. That means there is no statutory cooling off period. If she cancels she is likely to lose her deposit and, depending on the terms of the contract, the dealer may be able to take her to court for additional compensation. They may not do so - they may be happy to let the OP cancel without penalty. But that is up to them. The OP does not have any right a cooling off period.

Just phone and say statutory rights say I have a cooling off period

As others have said, there is no statutory right to a cooling off period. As the OP went in to the dealer there is no right to any cooling off period unless there is one written in to the contract.

There’s a cooling off period, just like when you change phone contracts. Don’t back down, don’t let them tell you it can’t be done. It can, go cancel.

Read the documents and contact the dealer. Legally you are bound to the contract, but they may have a cancellation clause or be willing to offer you a different car which is cheaper per month (they did this for me when my circumstances changed). But I would be surprised if they would be happy to fully cancel unless this was in the terms, speak to them today if you can.

Have you paid a deposit?

If so you will probably lose that, but you should be able to cancel the rest of the contract.

She wasn’t pressured.

Heavenly but OP wasn't pressured into signing?

You were pressured into signing and now want to cancel - don't grovel or make up excuses.

Be (almost) honest. Say some extra hours and pay at work you thought were confirmed turn out not to be and you can't actually afford the payments so you have to cancel.

I'd phone the car dealer and offer your apologies but say you're unable to proceed. If they are any good at their job, they'll be quite understanding (fed up about it, but my dB runs a car dealership and would rather keep the customer's goodwill)

That’s probably what paying a deposit covers. You can probably cancel, and they’ll keep your deposit. No point asking here though - you need to speak to the dealer ASAP. And it probably does without saying, but don’t be so easily manipulated in the future, especially when it comes to such large financial commitments.

Read your agreement. It will tell you if there is a cooling off period or if you can pay a small fee to get out of it.

Do you normally have trouble saying no? You could say no to the meeting. You couldn't say no to the new car. You should probably get some help for that.

Check the terms and conditions. Distance selling protections don't apply on the face of it (so no 14 day cooling off period), but if you bought the car on finance a cooling off period may still apply.

Have you actually paid anything?

You have a cooling off period. Cancel the agreement immediately no hard done!

Call them today and say your circumstances have changed and you will no longer be able to go ahead with the new agreement. I’m sure there must be a cooling off period but you need to speak to them sooner rather than later!

cancel the cheque

You should have 14 days cooling period.
I don't understand why you went in the first place if you didn't want a new car

If you are leasing rather than buying then I think there is a cooling off period.

Ask if there’s a cooling off period. They’ve got to be responsible lenders. You can’t afford it. You don’t have the car yet. Insist.

No cooling off period unless there's something in the contract (which is unlikely).

Can you appeal to them morally and practically? If you can't pay it, they will I cut so much money and hassle repossessing it. It's got to be worth a go.

Phone them, grovel and explain that your work situation has changed and you simply can't pay. They don't have to release you from the contract, but may wish to avoid problems with non-payment later, so you might get lucky.
It will be embarrassing for you, but it's either that or being stuck with a payment you can't afford.

Dh is motor trade, he says just cancel. He says kick off to customer services if they give you grief.

Cars fall out of bed all the time.

So what are you going to drive when current car lease ends?

Can’t believe you didn’t say no.

Worst case say you felt pressured and put on the spot and you dont want to have to escalate a complaint as mis selling so can they just cancel it. Bit harsh on the salesman but if it gets it cancelled and he doesn't actually get into any trouble then needs must.