The meaning of unemployment?

IN last Saturday's Financial Times, Noel Whiteside, Professor of Comparative Public Policy at the University of Warwick wrote a letter in which he questioned the method of measuring the unemployment figures.  Mr. Whiteside asked in a letter:

'What, in this day and age, does unemployment mean?  According to the Labour Force Survey (the most common measure) anyone who undertakes one hour's work per week is not 'unemployed' (even if dependent on state support as a working tax credit claimant).  It follows that, the more employment is structured in 40-hour (or whatever) work weeks, the more likely the unemployment statistics to measure fluctuations in economic activity.  Conversely, the more disorganised and casualised the labour market, the less likely the unemployment rate to measure such changes with any accuracy.  As the UK now boasts one of the most 'flexible' labour markets in Europe, both the failure of unemployment to rise as much as expected following the 2008 crash and the recent bizarre movements of the rate over recent months become understandable...'