It's become a familiar sight in the last five years ... the closing overs of the day, England batting, looking to play out time - and the camera shows the England balcony and James Anderson in pads and helmet, waiting once more to see if he'll be needed to see out the day. He is, of course, England's night-watchman, a curious tactic which seems to have no equivalent in any other sport.

Quite when the practice of employing a lower-order batsman - and the key word here is 'expendable' - to take the place of a more esteemed batsman at the end of the day is unclear. What becomes apparent from looking at the scorecards of the early Tests is that the batting order was often a fluid and flexible thing. In the days of uncovered wickets, which of course extended well into the 20th century, it was a common tactic when playing on a rain-affected pitch to push tailenders up the order - the correct term here I suppose is 'pitch-watchman' - in the hope that they could use up enough time for conditions to improve. This in turn led to specialist batsmen lurking low in the order, which is how Reggie Duff and WW Read both came to make hundreds from number 10. One William Bruce, one of many debutants for Australia in the second Test of the 1884-85 series, batted at 10 in the first innings and opened in the second. Since he ended his career with a batting average of 36, excellent for the time, but only 12 wickets from his 14 Tests it seems that his batting was his stronger suit anyway. Wilfred Rhodes was another who made the transition from last to first, although in his case it took a little longer. If we ignore bowlers pushed up for other tactical reasons, one of the first genuine night-watchmen seems to have been Hanson Carter, the Australian wicket-keeper who generally went in at 10 or 11, but who, in the third Test at Adelaide in 1911-12, batted at three in the second innings; he did his job, finishing 4 not out overnight. At any rate, the tactic must surely have been borrowed from county or state cricket.

And it is a tactic that seems more popular than ever today. Anderson had been an England player for four years by the time he first did the job, taking it over from the previous incumbent, Matthew Hoggard (there seems to be a designated player in each team, it's not something shared out among the bowlers) but he's since done it no fewer than 21 times. So, what are the qualities required? Well, first of all he must want to do it. There's no better story of the reluctant night-watchman than that of Robin Marlar, later an imaginative captain of Sussex but clearly unimpressed at the instruction to put the pads on. When he came back after two balls, stumped for 6, his response to his captain was "I told you I'm not a night-watchman." On that infamous evening in 1976 when Brian Close and John Edrich were being battered by the West Indies pacemen at Old Trafford, Tony Greig had to find someone prepared to pad up. Derek Underwood, England's regular at the time, refused point blank; Pat Pocock and Mike Selvey, without the same clout of seniority both did so, but thankfully neither was needed.

Also, the man chosen must be brave - he's unlikely to be facing spin from both ends - and reasonably competent. Phil Tufnell and Devon Malcolm, to my recollection, never did it, and with good reason. A stout defence is essential, and yet the following day can prove a nuisance, to both sides. Many a night-watchman has frustrated the fielding side the following day, even outlasting his overnight partner (Underwood's best Test scores of 45 and 43 were both made up the order, against slightly less ferocious bowling) but the player who can neither get out, or hit the ball off the square can hinder the batting side as well, taking vital time out of the game.

Tales of great batting deeds by night-watchmen are well-recorded, and I don't propose to list them here. There have been at least four hundreds, although it should be noted that one of those was by Mark Boucher and another was by Nasim-ul-Ghani, the former a highly competent wicket-keeper/batsmen and the latter an orthodox slow left armer. Alex Tudor would doubtless have joined them had he not been denied by Graham Thorpe against New Zealand in 1999. Yes, it's a team game, and the win was the main priority - but individual milestones are important as well, and I understand that Thorpe now regrets not giving Tudor more of a chance to make three figures.

Mention should be made of Australia, whose fast bowler Jason Gillespie might never have made his extraordinary 201 against Bangladesh if he'd been playing under Steve Waugh. 'Tugga' was opposed to the tactic; firstly, I imagine, because he felt that his batsmen ought to 'man up' and back themselves to last a couple of overs at the end of the day, and also, perhaps, because they mess up the batting order. And that's true if it leaves a competent lower-order player stuck at number 11, such as happened to Graeme Swann recently, or a 'proper' batsmen stranded for want of a partner. One of the very few incidents of a double night-watchman did just that. In 1978 New Zealand had taken a first-innings lead against England at Lord's and had a little over an hour to bat on Saturday; they must have been hopeful of being able to set a challenging target. But Willis and Botham proved too much of a handful and, amid the carnage, Stephen Boock and Brendon Bracewell were both sent out to try and see out the day. Boock was a reasonable tailend blocker but Bracewell a hopeless number 11 who made only one scoring stroke in six innings in that series; both were despatched, leaving New Zealand contemplating a close of play score of 37 for 7. On Monday no less a batsman than Geoff Howarth was left marooned on 14 not out at number 9.

So, is it still worth doing? In general I would say yes, when the circumstances are right - but it can be over-done. Going back to James Anderson, on two of the 21 occasions that he's been promoted, at Cardiff in 2009 and Dubai last year, he batted at number 8 - the batsmen he was sent out to protect were Matt Prior and Stuart Broad. Prior you could perhaps make a case for, although he strikes me as the sort who wouldn't want mollycoddling, but Broad is not a genuine Test match all-rounder, more a bowler who can bat. This was just tinkering, surely. The bowler is overworked enough today as it is; Test matches are played on pitches designed to last five days after all, and the one at Nagpur in the recent Test might well have lasted another five. So whenever possible he should be allowed to put his feet up once his day's work is done, and let the batsmen do the batting.