You only have to look as far as Channel Five's dismal October ratings figures to find the main reason for the departure of director of programmes Dan Chambers.
Five's all hours share is down 14% compared to October 2005. Year on year comparisons for the first 10 months of 2006 are little better - Five is down by nearly 11% on the same period of 2005, relatively speaking the worst performance of any of the five main analogue networks.
Even ITV1, which has dominated the headlines for most of the year with its summer ratings slump and the departure of ITV chief executive Charles Allen, largely because of the network's poor performance, is only down 7.5% year on year for the 10 months to the end of October.
Still, Mr Chambers' departure, after former Flextech programming executive Lisa Opie was parachuted in above him as Five's managing director of content yesterday, is a relatively ruthless move by the standards of the UK TV industry.
In recent times only the ousting last autumn of ITV Broadcasting chief executive Mick Desmond followed by the departure of director of programmes Nigel Pickard stands comparison in the ruthlessness stakes.
So while Five's executive cleansing is harsh on the affable, erudite Mr Chambers, owners RTL will feel justified in seeking change at the broadcaster's Long Acre HQ because ratings have been heading in the wrong direction - and at an accelerating pace - for the past 18 months.
Five's annual audience share hit a high of 6.6% in 2004, capping seven years of steady growth since the youngest of the five analogue networks launched in March 1997.
Last year Five was down slightly, to 6.4%; but this year the ratings slide is accelerating - the network is at 5.8% for the 10 months to the end of October.
Mr Chambers followed Kevin Lygo from Channel 4 to Five in 2001 and inherited his director of programmes role when Mr Lygo returned to Horseferry Road two years later.
He also took up - and expanded - Mr Lygo's strategy of trying to move Five upmarket, replacing the diet of films, football and soft porn that the broadcaster got by on in its early years with a broader palette of art and history documentaries, home grown popular factual programming and even the odd UK-originated comedy and drama.
In the early evening this proved a success, with critically lauded documentaries fronted by the likes of Tim Marlow and Brian Sewell, on subjects including poetry and philosophy, helping to improve Five's image immeasurably.
Ratings-wise, hardly anybody watched these high cultural fibre shows - but that did not really matter, because no-one had ever watched Five in big numbers between 7pm and 8pm.
Mr Chambers' bigger problems came after 8pm, where attempts to replace bought in movies and soft porn with homegrown programming has failed to produce a single breakout ratings hit.
He attempted to join the reality bandwagon unsuccessfully, with The Farm and Back to Reality; and a string of lifestyle, makeover and other popular factual programming has provided diminishing returns between 8pm and 11pm.
Even the Extraordinary People strand of "freakshow" documentaries has lost its ratings bite - last week's The Twin within the Twin drew just 1.5 million viewers.
Mr Chambers also attempted to get some original UK comedy and drama off the ground - but with similarly disappointing results.
All the while, the growth of Freeview has been pushing up multi channel penetration past 70%, increasing the competition faced by all the analogue networks.
But the pressure on Five is arguably particularly harsh, given that its annual programming budget, at around £200m, is less than half that of nearest rivals Channel 4 or BBC2.
The upshot of this is that on several nights last week peaktime shows on Five were getting less viewers than the top rating programmes on multi channel services.
Given the lack of new hits, Five is increasingly reliant on the CSIs, bought by former head of acquisitions Jeff Ford, and Home and Away - nicked off ITV by former director of programmes Dawn Airey back in 2000.
Five's newly launched digital services, Five Life and Five US, have come too late to save Mr Chambers, but should help Ms Opie by shoring up the broadcaster's multi channel share.
In terms of turning Five's performance around, Ms Opie's task is simple - find some hits.
And while Mr Chambers was rightly congratulated for commissioning more homegrown programming, the regrettable conclusion is that it has not worked commercially for him or Five.
So a change of direction in terms of Five's commissioning policy could be on the cards - maybe a move back to buying more US shows and movies is the way forward.
House, Grey's Anatomy and Prison Break have all done pretty good business for the broadcaster - although the superheated market for US programming could see Five, with its limited budget, struggling to compete with better resourced competitors.
Or how about a move to snatch a long running, well established, ratings banker from another UK broadcaster. Isn't the Neighbours contract up for grabs soon?
