World Cup 2015: England can challenge New Zealand - Guscott

The home nation has reached the final in five of the seven World Cups that have been held

With exactly a year to go until the 2015 World Cup in England, the hosts look the biggest threat to defending champions New Zealand.

The All Blacks may be red-hot favourites to lift the Webb Ellis Cup again, but they will enter the tournament knowing that no side have successfully defended their title.

Twelve months out, here's my assessment of the prospects for the home nations and other major teams.

England looking good - and getting better

Chris Robshaw led England to the Triple Crown in this year's Six Nations

Under head coach Stuart Lancaster, the England team have steadily improved and wins at Twickenham against Ireland and Wales in this year's Six Nations showed they are capable of performing under huge pressure.

England may have lost this summer's series in New Zealand 3-0, but the first two Tests - which they lost by five points and one point - were promising.

Given that Australia recently lost 51-20 at Eden Park, where England were only beaten 20-15 in June, I'm very optimistic about England's chances on home soil.

Some areas can be improved for England. The centre partnership is yet to be rubber-stamped, with Billy Twelvetrees still to give a stand-out performance that has allowed him to say: "This number 12 jersey is mine and I'm keeping it." Until he gives that kind of performance, he will continue to be questioned.

There are six or seven wingers in contention and, at fly-half, Danny Cipriani is making things interesting. Cipriani had an amazing game for Sale against Gloucester last Saturday, albeit in a losing cause. It's the best I've seen him play since before he moved to Melbourne in 2011 and if he carries on playing like that this season he'll certainly leapfrog Bath's George Ford in the pecking order.

Cipriani and Ford attack flatter, harder and quicker than current England first-choice Owen Farrell. But Farrell is standing flatter himself of late and has undeniable composure, a strong will and is stronger physically. And, as he showed in this year's Six Nations, he allows the rest of the back-line to play. That's why Lancaster thinks so highly of him and why he is the standard to which Cipriani and Ford must aspire.

Chris Robshaw will always be scrutinised more than most other players, simply because he is captain. Two games into the Premiership season, Saracens' Will Fraser is already being mentioned as his possible open-side replacement.

I don't see a massive difference between them. Fraser's Saracens thumped Robshaw's Harlequins last Friday, but everyone in the Sarries pack looked better than their opposition number that day. And only if you can regularly create more turnovers and concede fewer penalties will you challenge Robshaw for his England place.

No side can match New Zealand's fitness

The All Blacks beat England 3-0 in the Test series in New Zealand this year

New Zealand have been awesome in this year's Rugby Championship and the reason they are out there on their own is simple: they are fitter than every other team. People talk about their skill, but what underpins that is their fitness.

When Clive Woodward took over as England head coach in 1997, he said to us: "How can you expect to beat the All Blacks when you're not as fit as them?" It was commonsense and for a period between 2000 and 2003, when they won the World Cup, England were probably the world's fittest team.

At the moment, I can't see any side willing to make that improvement. If you were as fit as New Zealand you could, theoretically, tackle or run them off the park. But while other sides are bigger, they are unable to run hard for 80 minutes or suddenly flick the switch and up the tempo, like the All Blacks do.

England proved in the summer that the All Blacks are beatable, and the world champions have been pushed close by Australia and South Africa in recent weeks. In addition, New Zealand have their off days, especially at World Cups, but I still expect them to make history by retaining their crown.

Early exit for Wales or Australia

Wales wing George North was the first teenager to score 10 Test tries

You look at the calibre of player Wales have in their team and you think they're good enough to beat the best. But I doubt whether Wales have that necessary creative spark to win the World Cup.

Like Wales, South Africa are a route-one side but they are much more physical.

If you make your front-line tackles against Wales, they don't seem to have anything else up their sleeves other than sending Jamie Roberts, George North, Alex Cuthbert and the rest of their big guys into the wall.

England will progress from Pool A, the so-called 'group of death', so it's a toss-up between Wales and Australia as to who will perish.

Australia's performance against Wales last autumn was fantastic, but that win was orchestrated by half-back pairing Will Genia and Quade Cooper, and they have been injured of late.

Ireland's big-match players & Scotland's mental hurdle

Ireland captain Paul O'Connell bade farewell to the great Brian O'Driscoll after this year's Six Nations

After their Six Nations triumph in 2014, I can only see Ireland improving, despite the retirement of the great Brian O'Driscoll. Professional sport is about putting aside disappointment and moving on, and that's what Ireland will do.

As well as Ireland winning the Six Nations, Ulster, Munster and Leinster topped their Heineken Cup groups and Joe Schmidt is a very smart head coach who can get more out of this side than he already has done.

In the absence of O'Driscoll, Ireland have enough big-match players in their squad - Paul O'Connell, Sean O'Brien, Jamie Heaslip, Rory Best, Jonny Sexton, Rob Kearney - to make an impression. There's no reason they can't go far at the World Cup.

Vern Cotter was a very successful coach with Clermont in the French Top 14, but the Scotland team he inherited have a big psychological hurdle to get over in trying to change from perennial underdogs to contenders.

They haven't been able to score tries and they've struggled to find a consistent fly-half. And if you haven't got a consistent number 10 or he isn't given enough time to bed in, you can't expect consistent performances from your side.

Willie le Roux has scored seven tries in 19 Tests for South Africa

Springboks stuck, France in big trouble

I get the impression South Africa head coach Heyneke Meyer is trying to change his side's playing style, but changing a culture takes time.

Last season in Johannesburg the Springboks ran at New Zealand and, while they lost 38-27, it was a brilliant, thrilling game which featured nine tries. But I haven't seen anything like that from the Springboks since.

In this year's Rugby Championship they haven't scored many tries and have missed quite a few tackles, which is partly down to Meyer's decision to introduce 20-year-old Handre Pollard at fly-half.

They have an unbelievable back three in Bryan Habana, Cornal Hendricks and Willie le Roux and if they could get more ball they would be far more dangerous.

The players in the French squad are proud guys and the Top 14 is a brilliant competition but it affects the national team because there are a lot of imported players and the home-grown talent struggles to break through.

France are in big trouble - there is nothing to suggest they are in the right position to challenge for the World Cup. Then again, you would have said that in 2011 and they reached the final and almost won it.