Members sometimes wonder whether taking strike action ever makes a difference.
Thankfully, David Gauke, Exchequer Secretary to the Treasury, the minister with responsibility for HMRC, gave a very clear example of the impact it has on the department in his answer to a parliamentary question, copied in full below.
Not only is it clear from the answer what the impact was on the week of rolling industrial action – where no member lost more than one day’s pay – but the impact on the following week was even more severe.
We would like to take this opportunity to thank Mr Gauke for his honesty and encourage members to bear this in mind the next time we have to act.
Ian Lavery: To ask the Chancellor of the Exchequer how many call attempts were made to HM Revenue and Customs contact centres on each working day between 3 June and 15 June 2013; how many such calls were answered by HM Revenue and Customs contact centres; and how many answered calls led to a request for a needs enhanced support face-to-face meeting. 
Mr Gauke: HM Revenue and Customs contact centres received and answered the calls in the following table during the period requested.
Between 3 and 7 June, regional industrial action taken by Public and Commercial Services Union members in HMRC, DWP and VOA led to reduced staffing in many contact centres, with increased demand therefore impacting later weeks.
84 telephone requests resulted in 14 needs enhanced support face-to-face meetings in the north east pilot area. The remaining needs enhanced support calls were resolved over the phone. HMRC continues to work on developing its pilot to ensure all customers who need additional help receive it.