Now is a popular time of year for consumers to consider taking out a 0% credit card to help spread the cost of Christmas.

But it can take up to 30 days for a card to be approved so you need to act quickly.

More transparency from credit card companies about interest rates would be better for consumers, according to industry observers, because although credit card companies are apparently in cut-throat competition to offer the longest ever 0% purchase and balance transfer deals, not all applicants will qualify.

Recent research by thinkmoney indicates that eight million adults in the UK expect to have to borrow money to pay for Christmas this year.

Most people would like to clear their debts as quickly as possible but it is useful to have the flexibility to spread repayments at this time of year.

Not having to pay interest on your credit card balance means it can be cleared more quickly because despite no change in base rate, the average interest rate on credit cards has crept up from 18.9% to 19% APR over the past year according to Moneyfacts.

If you are primarily interested in spreading the cost of new purchases, the best deal is currently being offered by the Tesco Clubcard credit card. It has 0% deal for 18 months. If you normally shop at Tesco anyway, you will also be able to collect extra Clubcard points by paying with this card.

Other top deals for 0% on purchases are offered by Halifax and M&S. Their credit cards allow you to spread repayments over 15 months interest free.

With the M&S card there is the added bonus that you accumulate M&S points when shopping (not just at M&S) for which you get reward vouchers that can be spent in store.

Existing balances on other credit cards can also be transferred onto 0% deals. However, the 0% periods for balance transfers may be different which can be confusing when you are trying to plan your finances.

With the Tesco card offering 18 months at 0% on purchases, a balance can be transferred at 0% but only for 9 months, while with the M&S 15 months 0% deal on purchases, balance transfers are interest free for 12 months.

However with the Halifax All in One credit card, both purchases and transfers will remain interest free for 15 months.

The longest 0% deal on balance transfers is currently being offered by Barclaycard which has recently extended the zero interest rate period on its Platinum Visa card to 30 months. But purchases on this card are only interest- free for six months.

Meanwhile, Tesco also has a credit card with a longer 0% period for balance transfers of 28 months, but this card only charges 0% on purchases for three months.

The problem with many of the best 0% credit card deals is that providers will only accept you if you have the right credit profile.

Charlotte Nelson of Moneyfacts says: "The credit card market has heated up over the past year, with many introductory and balance transfer deals increasing to record highs (but) advertised rates are only need to be given to 51% of successful applicants, so consumers need to be wary that the rate of interest they receive may not be what they originally anticipated."

Paul Lawler of Moneysupermarket says: "Most providers aren't very transparent about what they will offer if you don't qualify for the advertised deal and most will do 'hard' searches with credit reference agencies so other providers will be alerted to the fact that you are seeking credit. It would make life easier for consumers if providers were more transparent and only made 'soft' searches. It would make it easier for people to shop around."

However, consumers can get a rough idea of which 0% cards they might be accepted for by using Moneysupermarket's online credit card 'smart search' tool which asks a few questions about their personal circumstances such as employment status and income.

It will than list cards you are most likely to qualify for, although Mr Lawler admits it is no guarantee. If you don't qualify for the top deals, there may still be others available. Matt Sanders of Gocompare points to cards such as Barclaycard's Initial Visa or Capital One's Classic Visa which both offer 0% interest for three months on purchases.

A major consideration if you are considering a balance transfer is that you will be charged a transfer fee. Typically these are around 2.5% to 2.99%.

So for every £1000 you transfer another £25 to £30 will be added to your balance on the new card. But there are some special offers on these fees too. Halifax, for example, is offering a balance transfer fee refund on its All in One card, which offers 15 months interest free on purchases and balances, bringing the fee down from 3% to a real bargain 0.8%.

With Barclaycard's Platinum Visa card offering a 30 month 0% transfer deal, you will initially pay 4.9% but this will be reduced to 2.9% by refund.