When Ian Bell is playing well, there are few better sights in cricket. No matter what the match situation, he has an assuredness and solidity that immediately calms dressing-room nerves, while his grace and elegance makes batting look like one of the easiest tasks in the world.

The problem, though, is that Bell hasn't been playing well for much of the last few years. Since the start of the 2013-14 Ashes series in Australia, in 19 Tests (34 innings), Bell has averaged 28.48, with only two hundreds - one each against India and West Indies. While that itself is a pretty long run of poor form, Bell's lean spell runs even longer than that, though interspersed by a couple of exceptional series: since the beginning of 2012, Bell's average in 43 Tests (78 innings) is 34.28, which is well below what you'd expect from a player of his class and ability. The one exceptional series he has had during this period was the home Ashes contest in 2013, when he was by far England's best, scoring 562 runs at 62.44, in a series in which no other England batsman touched 400. Bell was colossal in that series, but on either side of that series have been barren spells which hardly do justice to a batsman of his calibre.

Over the last three-and-a-half years, Bell's stats are unquestionably one of the poorest for specialist batsmen. Among batsmen in the top six who've batted at least 40 innings - there are 28 on that list - only Shane Watson has an average lower than Bell's 34.69. Given that Watson has also bowled a bit during this period - 18 wickets at 33.50 - Bell's average is the worst among specialist batsmen. In these 43 Tests, the overall average for all players who batted in the top six was 37.41, which means Bell was about 7% poorer than the average specialist batsman. There are three other England batsmen in the list below, but Jonathan Trott and Kevin Pietersen are no longer in the England squad, while Alastair Cook has clearly regained his mojo after a long lean spell.

England's best during this period, Joe Root, has averaged 55.22, and is one of nine batsmen with 55-plus averages. Hashim Amla is on top of that list with an average of 65.73, while Steven Smith, Shivnarine Chanderpaul, Kumar Sangakkara and AB de Villiers have all averaged more than 63. It's true that England have tended to play in relatively low-scoring games compared to some of the other sides - the overall top-order average in the 28 Tests AB de Villiers played during this period is 41.03, compared 37.41 for Bell - but even so it's clear that Bell has underperformed, especially given that he has been one of England's senior batsmen during this period.

Since the beginning of 2012, Bell has played 14 Test series (including the ongoing Ashes). In nine of them, he has averaged less than 35, including the current Ashes where he has scored 73 runs in four innings. Against New Zealand earlier in the home season, he managed 43 in four innings, and while he got 155 from five innings in the West Indies, 143 of those were scored in one, and 12 in the remaining four.

A break-up of his scores indicates that in the last three-and-a-half years he has been getting out for single-digit scores once every three innings, and for less than 20 more than 50% of the time. His tendency to get out very early in his innings has always been relatively high for a middle-order batsman - Michael Clarke, for example, gets out for less than ten in 29% of his innings - but the difference recently has been Bell's dismissals between 10 and 19, which has gone up significantly compared to earlier in his career. And then there has also been the inability to convert starts into really big scores: he has been dismissed between 50 and 65 ten times since 2012.

One of the most disappointing aspects for Bell over his entire career has been his inability to become a strong batting force up the order. He will get another opportunity at No. 3 at Edgbaston, with the selectors having announced the batting order for the Test, but his record isn't encouraging: in 87 innings at Nos. 3 and 4, he averages 35.84, with only six hundreds. Against Australia at these positions he averages 23 from 30 innings, though it's true that he does better at three than he does at four. In the current England middle order, though, he is clearly the senior-most, and needs to put his hand up and take on more responsibility.

Even during his relatively lean period, it isn't as if Bell has played key innings to rescue England, but most of those innings came in the 2013 Ashes, when he was in outstanding form. His 109 at Trent Bridge came at 121 for 3 in the second innings, after England trailed by 65 after the first; when he made 109 at Lord's he came in at 28 for 3; his 113 at Chester-le-Street again came after England had conceded a slender lead and lost three quick wickets in the second innings. They were all tough runs, against a difficult bowling attack, and helped England win, but since that series he has hardly ever done that, and even through his entire career the tough runs haven't come often enough for a player of his class.

For a batsman with so many form issues over the last three years, Bell has remarkable numbers during this period against Australia's two main strike rate bowlers, Mitchell Johnson and Mitchell Starc. Against Johnson, in 11 innings, Bell has been dismissed only once, scoring 73 runs in 148 balls; against Starc, he has stats of 2 for 86 in 154 balls. In the ongoing series, though, both Johnson and Starc have got him out once each.

Other bowlers have posed plenty of problems for Bell, however. Ryan Harris has dismissed Bell five times for 120 runs, which means Bell will be thankful he isn't around for this series. Offspinners have bothered him too, with Saeed Ajmal and Nathan Lyon both dismissing him twice. Overall during this period, right-arm bowlers have troubled him a lot more than left-arm ones.

Bell's Test career is now in its 11th year, but despite some periods of excellence, his overall report card isn't outstanding. When he had those two tremendous years in 2010 and 2011 - he averaged almost 82 in 20 Tests - it seemed he was taking his game to the next level and would be one of the leaders of England's batting for the next several years. Some of those runs were admittedly soft - against Bangladesh, Sri Lanka and India - but he also played a couple of tough innings in South Africa, and contributed prominently in a famous overseas Ashes triumph. After the home season of 2011, his career average was on the verge of touching 50 for the first time since 2005 - it was 49.28, and one great Test match at that stage would have pushed his average beyond 50.

Sadly, though, that great Test match never came. By the time he scored all those runs in Ashes 2013, his career average had dipped to 45; currently, it has fallen further to 43.18, more than six runs off that high of 2011. Apart from that 20-Test stretch in 2010-11, Bell has averaged 37.42 in 92 Tests over his career, which isn't exactly stellar. Among the 34 top-order batsmen (batsmen in the top six) who've played at least 75 innings since the beginning of 2005, Bell's average of 43.22 is 28th, with only Paul Collingwood, Brendon McCullum, Tamim Iqbal, Andrew Strauss, Mohammad Hafeez and Watson averaging worse than him.

All of this will be forgiven, of course, if Bell notches up a couple of hundreds over the next few weeks.