home renovation - deposit requested

This is a bit of a shot in the dark as it relates to a problem my son has who lives in the UK.

He has received a quote from a builder to do some renovations to his home. He is still awaiting approval from his mortgage provider for the additional funds. However, the builder wants him to pay him a deposit of £2k to hold a starting date of mid October. Says he has other jobs on offer and needs to ensure my son goes ahead with this. In my view this is more like asking for a guarantee without any guarantee that the builder will even turn up. Personally, I wouldn't hand over £2k before any building starts. Given the pressure these days finding a builder here and in the UK, they seem to have the upper hand now.
However, if my son fails to get the money from the bank he may have to cancel the work. If he hands over the £2k the builder can just walk.

Am I being too pessimistic? Any other way of doing this so that he can engage the builder but be sure he won't lose his money.

There are lots of factors involved. How do he get to hear about the builder ? What is the builder buying with the 2 grand ? Is it just a deposit ? I would be very reluctant to hand over anything unless I knew the builder or he was vouched for by a reliable source. Deposits are usual to buy material up front rather than just to keep the builder on side. I think your hunch is right.

A few previous AAM threads on this subject .

Maybe getting a solicitor involved might be the only route but even then the builder could go bust between now and October.

Having watched a few of those programmes from the UK of 'Don't get done, get Dom' about builders it only confirms the suspicions expressed in those threads.

I’d advise against going deposit as it may not be secure.

Thanks all for your replies. Builders come from one of those sites where tradesmen are suppose to have recommendations behind them.
Yes, the £2k is just to hold the date! I know it is very difficult at the moment to get builders here and in the UK to do smaller jobs like this one that my son is planning. However, having had work done ourselves about 10 years ago, our builder never asked for a deposit - just staged payments and all that went well.
I think getting a solicitor involved as mentioned by Sue Ellen may be an alternative. I had suggested something on the lines of having the solicitor hold the 2k until the date of commencement and then agree on stage payments. Unless my son does something like that he is handing over money to complete strangers who although they've checked out online as having a good record, he really doesn't know them. Great to get your views too.

Personally I wouldn't hand any money over unless, for example, the builder was going to use the £2k and deliver goods and supplies to be used in the work. At least that way your son has something. An alternative would be to pay via credit card and there would be options to raise a chargeback for 120 days after making the payment if he didn't turn up.

I don't trust those sites, too easy to create fake reviews.

Most building works of any scale here will require a deposit up front. If you don't trust the builder you chose to carry out renovations not to run off with 2k, find another builder.