We're the UK’s leading business telephony and cloud communications provider.
Delivering IT services, contact centre technology, unified comms, fixed-line voice, connectivity, and managed cloud solutions.
Join our Team as a ITMS 3rd Line Technician!
Location: Swindon
Salary: Competitive
Hours: Monday - Friday - Shift based between 08:00 - 18:00
About the role:
As an ITMS 3rd Line Technician, you’ll be the go‑to expert for the toughest technical challenges—stepping in when issues go beyond First and Second Line support. You’ll take ownership of critical incidents, shape infrastructure improvements, and play a key role in guiding and developing junior team members. This is a role for someone who thrives on solving complex problems, enjoys collaborating across teams, and wants to make a meaningful impact on both customer environments and internal processes.
What makes you a great fit:
* Exceptional analytical and problem‑solving ability, especially under pressure
* Strong leadership qualities with a passion for mentoring others
* Clear and confident communication, able to translate technical detail for any audience
* High sense of ownership, accountability, and proactive thinking
* Ability to juggle multiple priorities while maintaining quality
* Deep expertise across cloud, networking, and infrastructure technologies
* Strong documentation habits and experience working to SLAs
* Empathetic, professional approach to customer interactions
* Team‑focused mindset with a drive to share knowledge
* Proactive, adaptable, and creative in resolving issues
* Strong organisational skills with the ability to meet deadlines
* Commitment to continuous learning and self‑development
Key responsibilities:
* Act as the final escalation point for complex technical incidents and service requests
* Lead root cause analysis for recurring or high‑impact issues and implement long‑term fixes
* Work with project and solutions teams on infrastructure upgrades, migrations, and deployments
* Proactively maintain and manage customer IT estates, ensuring security, performance, and accurate documentation
* Recommend improvements aligned with best practice and evolving customer needs
* Provide technical leadership and mentoring to First and Second Line teams
* Create and maintain technical documentation, including diagrams, SOPs, and troubleshooting guides
* Own change management processes, ensuring risk assessments and rollback plans are in place
* Monitor system performance and identify opportunities for optimisation or automation
* Liaise with vendors and third‑party providers for advanced support
* Contribute to continuous improvement of tools, processes, and service delivery
* Travel to other Onecom offices and customer sites when required, following company travel policies
Perks for our People:
* Holidays: 25 days + bank holidays and buy/sell options
* Other Leave: Birthday day off, 12 paid hours for flexible use, Volunteer day
* Lifestyle: 9% combined pension contribution and 4x salary life assurance
* Rewards: Quarterly and annual employee awards, discounts on tech
* Socials: All-expenses-paid company events
* Development: In-House Training Academy
* Wellbeing: 24/7 access to mental health support, Calm App, discounted gym membership, free breakfast & fresh fruit, eye-care vouchers, financial wellbeing support
Who we are:
Onecom is an award-winning provider of Communication Technology, trusted by UK organisations to deliver Simply Brilliant Customer Experiences.
ED&I:
We are committed to equity, diversity, and inclusion, and we encourage candidates to complete our equality monitoring form as part of the application process. Responses are anonymous and help inform our future initiatives.