UK manufacturing IT/OT convergence has been talked about for a decade. In 2026, NIS2 + IEC 62443 + targeted ransomware attacks have made it operationally urgent. This is the practitioner's view from Servnet engagements with UK automotive, aerospace, F&B, pharma, and chemicals customers.
The IT/OT divide and why it matters
IT — office network, email, ERP, CRM, file shares. Refresh every 3-5 years. Patched monthly. Microsoft + Linux dominant.
OT — PLCs, HMIs, SCADA, MES, historian. Refresh every 10-20 years. Patched annually or never. Siemens, Rockwell, Schneider, ABB dominant.
The divide existed because OT couldn't tolerate IT-style patch cycles. But in 2026 the air-gap is gone — OT needs internet for remote support, analytics, and predictive maintenance.
The Purdue model in 2026
Level 0-1 — Process (sensors, actuators).
Level 2 — Control (PLCs, HMIs).
Level 3 — Operations + manufacturing execution (MES, historian, SCADA).
Level 3.5 — DMZ between OT + IT.
Level 4 — Enterprise IT (ERP, CRM, business systems).
Level 5 — Cloud + internet.
2026 reality: strict layer separation is increasingly impractical. Modern OT security focuses on monitoring + segmentation + identity-aware control rather than air gap.
The practical 2026 stack
OT asset discovery — Claroty / Nozomi Networks / Dragos for passive monitoring + asset inventory.
Network segmentation — Fortinet FortiGate or Palo Alto NGFW enforcing IEC 62443 zone/conduit.
PAM for engineering access — CyberArk or BeyondTrust hardened jump server for OEM remote vendor access.
OT-aware SIEM — Microsoft Sentinel or Splunk with ICS protocol parsing (Modbus, DNP3, IEC 61850, OPC-UA).
24/7 monitoring — co-managed or fully-managed MDR with OT-aware threat hunting.
Common UK manufacturer gaps
"We don't have OT cyber issues because we're air-gapped" — almost always wrong. Engineering laptops move between OT + IT. Vendor remote access uses dial-up modems still in production.
OT asset register is a 10-year-old spreadsheet — actual count typically 20-40% higher than recorded.
No incident response plan for OT — IT IR plans don't cover production stoppage.
IT/OT shared credentials — shared admin accounts across plant + corporate.
What Servnet does
Servnet supports UK manufacturers across automotive, aerospace, F&B, pharma + chemicals. Engagement: 1) OT asset discovery + segmentation gap analysis, 2) IEC 62443 + NIS2 alignment, 3) deployment of identified controls, 4) ongoing managed OT + IT cyber.