You can watch the TV series Madam Secretary through several options:

• Streaming Services:
  • Available on SkyShowtime in the Netherlands with a subscription (about €5.99/month after a 7-day free trial), allowing you to stream all 6 seasons in HD

* In the UK, it is available to stream for free with ads on **UKTV Play**

* It is also available on **Apple TV** and **Amazon Video** for purchase or download in various regions

• Purchase or Rent:
  You can buy episodes or full seasons on platforms like Amazon Video , Apple TV , and Fandango at Home starting around $2.99 per episode

. In the UK, episodes start at about £2.49 each

• Amazon Prime Video:
  Madam Secretary is available on Amazon Prime Video in some locations, though availability may vary by region

To summarize, your best options are subscribing to SkyShowtime (if in the Netherlands), streaming free with ads on UKTV Play (if in the UK), or buying episodes/seasons on Apple TV or Amazon Video. Check the service availability in your country for the most convenient option