Nobody can predict the affects of Brexit but it is wise to consider them.
We saw the pound weaken after the vote to leave and it is possible the pound will weaken further after Brexit and this devaluation could be quite dramatic.
If that happens it is likely to increase inflation, UK inflation has gone from under 1% around the time of the referendum to 3% today and it could well go higher.
If inflation continues to increase, the Bank of England is likely to put up interest rates, as it has historically done this to hedge against inflation. We have been living in a world of artificially low interest rates since the global crash of 2008 as the BoE has tried to stimulate recovery with lower rates. The rates cannot continue at this level if inflation starts to rise.
That in turn will put up mortgage rates. So for example if you have a £100k mortgage at 3.92% (currently this is a reasonable rate to have) your repayments will be £523 a month. If your mortgage rate goes up to say 7% then your repayments are £707 a month, if it goes up to 10% then it's £909 a month and so on.
There is a mortgage calculator you can use to try playing with different amounts here:
My advice would therefore be try to get as small a mortgage as you can and make sure you can afford it quite comfortably, in case rates go up and you need to find a few hundred pounds a month extra.
There are other risks from Brexit as well, house prices could fall as people decide not to buy properties due to excessive interest rates!
Overall nobody knows what will happen but it is good to be planning ahead for all eventualities.
** I am not a financial advisor, this advice is given in good faith but with no financial qualification.