FOR HUNDREDS of thousands of homebuyers across Scotland, the last few months have been full of uncertainty. Will base rates rise further? When might it happen? What will the impact be on mortgage costs? And what should borrowers do next?

Despite last week's decision by the Monetary Policy Committee (MPC) to leave rates unchanged for one more month, most experts believe we are set to face a further rise some time this year. In turn, this has left many borrowers asking themselves the same questions once again.

Yet while some answers - perhaps it would be better to call them predictions - are reasonably well known, others are less clear.

Ray Boulger, senior technical manager at mortgage broker John Charcol, sees the debates within the MPC as important: "The interesting point about the minutes of the last MPC meeting was that of the nine members there, eight voted to keep rates as they were and one voted for an immediate rate cut."

This, Boulger points out, was unexpected; if anything, the view among experts had been that one or two members might vote for a rise but be outnumbered by those holding firm.

The lone voice pushing for a cut was also unusual, in that it came from David Blanchflower, a US-based economist. "He clearly has a better idea of what is happening in the US housing market," Boulger believes. "It is becoming evident that the market there is suffering a slowdown and, while the impact will take time to work its way through the US economy, it will be felt as time goes on."

In turn, this increased pressure is not just on the US Federal Reserve but also on the Bank of England to keep rates lower, which is why Boulger predicts base rates in the UK may rise by another 0.25 percentage points this year before falling back within the next 12 to 18 months.

The impact of this view can also be seen in the money markets. Two-year "swap rates", a major determinant of mortgage rates, peaked at about 5.8% recently, after rising 0.4% since just before Christmas, but have since dropped slightly.

The result has been that mortgage lenders are currently offering marginally lower fixed-rate products than at the beginning of the year. Moreover, as Ray Boulger points out, they are doing so at prices lower than current swap rates: "Many lenders will make the offer now but not fund it straight away, in the hope of being able to buy the money in tranches and obtain a cheaper rate further down the line."

For example, Royal Bank of Scotland last week launched a two-year fixed rate at 5.19%, with a product fee of only £499. Also available is a two-year base rate tracker, priced at 0.3% below Bank of England base rates. This gives an effective mortgage rate of 4.95%, albeit with product fee of £999.

Alternatively, Newcastle Building Society is offering a new two-year fixed-rate mortgage of 5.22% until April 30, 2009. The deal comes with a £475 completion fee and higher lending charges are not levied up to 90% of a home's loan-to-value.

Other lenders are appealing to those who fear continuing uncertainty in the mortgage market. For example, Leeds Building Society last week launched a 10-year fixed-rate mortgage at only 5.39%, with an £849 completion fee. A fee-free version is available, but priced at 5.99%.

Nationwide Building Society has gone for an even longer-term fix, this time for 25 years. Its rate of 5.49% claims to be competitive against most five-year deals, while those worrying about being locked in for that length of time are being reassured that there will be no early repayment charges - but only after 10 years Louise Cuming, head of mortgages at price comparison website Moneysupermarket.com, says: "The Nationwide offering is interesting but unless you have a crystal ball to foresee your own situation and future interest rates, it is ludicrous to allow yourself to be tied into a contract for this length of time.

"Not only this, but interest rates are expected to start reducing next year, so it makes no sense to commit now to what is potentially a high rate of interest."

Julia Harris, mortgage analyst at the Moneyfacts comparison site, adds: "This will only suit a niche market of borrowers who still have the majority of their mortgage term remaining."

As for which mortgage to look at now, Ray Boulger is prepared to take a punt: "In my view base rates are at or near the peak and we will see them falling a bit over the next 18 months.

"If I had a choice between a fixed rate or a tracker I would probably opt for the latter. That said, a fix is the right solution if you can't take the risk of being wrong."