More Scottish Property News.

Estate agents last month registered four house-hunters to every available property. Gary Smith, president of the National Association of Estate Agents (NAEA), said: "NAEA members are showing that there are buyers aplenty out there.

"More often than not these are also potential sellers who are at the beginning of the process, so there is bound to be a lag which creates a shortage of properties in the short term."

But anyone thinking of buying a house - or switching their mortgage - could pay a high price as almost all lenders have raised the cost of their fixed rates over the past few days.

Royal Bank of Scotland (RBS), for example, has put up the rate on a two-year fix from 3.19% to 3.69%.

Britannia has also increased the cost of some of its mortgages. A buyer with a 10% deposit will now pay 5.99% for a two-year fix - a big jump from the previous rate of 5.09%.

Then there's Nationwide, which has raised rates twice in as many weeks. A three-year fix with a 25% deposit now costs 4.98%, up from 4.54%, which was an increase from the previous rate of 4.28%.

So why have mortgage rates been rising when the base rate has not moved? David Carmichael, head of independent mortgage broker Savills Private Finance Scotland, says: "Lenders price their fixed-rate mortgages according to so-called swap or money market rates, not the base rate. And money market rates have been rising, so banks and building societies are reacting accordingly."

The average two-year fix has jumped 0.32% in the past two weeks from 4.74% to 5.06%, according to Moneyfacts. The typical rate on five-year deals has climbed slightly higher, up from 5.61% to 5.98%.

Michelle Slade, analyst at Moneyfacts, says: "After a period of relative calm in the mortgage market, lenders are stumbling over each other to increase fixed-rate mortgages. The last time we saw such frantic activity was at the end of June 2008, when the average two-year fix reached a staggering 7.08%."

The rise in swap rates might have triggered the recent bout of increases, but lenders have also wasted no opportunity in boosting their profit margins. Ms Slade says: "In June 2008, when the average rate hit its peak, the margin over swaps was 0.76 percentage points. Today the margin is 2.81 points."

But borrowers can still fix their mortgage rate for two years at less than 4% if they are prepared to hunt for a good deal - and they have a decent deposit. First Direct, for example, has a two-year fix at 3.49%. The minimum deposit is 25% and the fee is £1498.

Or there's a three-year fix from Chelsea building society at 4.09%, with a £995 fee - but you need a bigger deposit, of at least 35%. If you can't manage that but can provide a 25% deposit, you can fix for three years with First Direct at the slightly higher rate of 4.29% with a £998 fee.

Borrowers who want to fix for longer might consider the five-year deal from the Post Office at 4.45%. The minimum deposit is 40% and the fee is £599. Alternatively, RBS offers a fix at 4.89% on a 25% deposit and a £299 fee.

Experts advise anyone who is thinking of fixing their mortgage to act quickly. David Hollingworth, a broker with L&C Mortgages, says: "The rise in swap rates indicates that the markets expect the base rate to rise in the future as the economy recovers - and it's difficult to see how it can fall lower than its current level of 0.5%. Swap rates have also been rising gradually for some time and there is nothing to suggest they will come down."

You might even find that a delay weakens your bargaining position. "If the value of your house falls while you are waiting to fix, it could affect the size of your deposit, which could exclude you from some of the very best deals," says Hollingworth.

In the past, two-year fixes have proved popular because borrowers are wary of locking into a rate for too long. But Carmichael does not dismiss longer-term deals. He says: "More borrowers are now fixing for five, seven or even 10 years because these deals are pretty competitive."

But is it a good idea to fix, especially if you are lucky enough to have a cheap tracker or pay a low standard variable rate (SVR) of about 3%? A number of lenders are also cutting their tracker rates. Katie Tucker, technical manager of Mortgageforce, says: "A borrower with 20% deposit considering Nationwide's new rates can have a two-year fix at 6.28%, or a tracker at 5.23%. That's a huge difference of £114 in monthly interest payments on a typical £130,000 mortgage."

If tempted by trackers, plan for a future of higher costs. Hollingworth says: "It seems illogical to switch to a mortgage with a higher rate, but if you stick with your current variable deal, you should remember that the base rate can go up quite significantly and quite rapidly. Also, when you are ready to switch, fixed rates will almost certainly be higher than they are now."