Job Description

Recruiter: Krystle James
Hiring Manager: Matthew Marshall
Career Grade: E
Internal Closing Date: 10/06/25
Security isn't always the first thing that comes to mind when you think of BT, but when it comes to keeping everyone safely connected, We Are The Protectors. We deal with thousands of cyber-attacks every day, so that millions of people can safely go about their daily lives and run their businesses. We deliver vital work at scale, with real breadth and impact. We connect for good.
You'll be joining a specialist security team that is a trusted partner to governments worldwide, protecting critical national infrastructure and committed to the safety and security of our nation and global communities. Our mission focused work is innovative, inspiring and technologically challenging in a way that makes every day different and stimulating. We provide the opportunity to work on rare projects, with exciting tools and brilliant people. Everyone has access to unparalleled professional and personal development opportunities and your contribution is always valued.
Why this job matters
Our team develops, maintains and operate big data platforms for one of our major customers. Comprised of Apache Hadoop components, Elasticsearch, and a significant number of in-house developed applications to simplify end user's interactions with the platforms, these are built on a large remote Linux (predominantly) estate. The platform supports a suite of tools for storing, enriching, querying and visualising large amounts of data. The requirements can change at short notice, so the team uses a DevOps methodology to react to these changes and continue to provide the best customer service.
In this role you will be a key driver in improving our customer's cyber capability. The customer will look to you as one of the technical experts for a range of activities where you will have the opportunity to develop your skills in many areas. You must be a self-motivated individual, with the ability to make changes that improve our services and will be involved in short-, medium- and long-term strategy for this customer and wider BT security policy.
Due to the sensitive nature of this role you WILL be required to undergo DV (Developed Vetting) level Security Clearance (https://www.gov.uk/government/publications/united-kingdom-security-vetting-clearance-levels/national-security-vetting-clearance-levels). An allowance of xc2xa35k per annum may be payable monthly while you hold this DV and continue to work in a role that requires that level of security clearance. The terms of this allowance will be made available if you are successful in being recruited into this role.
This role is based in London. Onsite (5 days office based). Monday-Friday between the hours of 8am-6pm (flexible) 37.5 hours per week. You must already have DV UKIC clearance to start this role. Must have lived in UK for 10 years+ in order to attain this clearance.
What you'll be doing

• Responding to issues that are raised either by automated dashboards, by our users, or through proactive monitoring routines that you will develop.
• Looking at existing dashboards and creating new ones to monitor systems.
• Writing new system critical applications for high volume, high velocity record analysis and innovative query based on our user's requirements.
• Looking for performance improvements in the existing codebase, or researching and implementing new ways to store and query the data.
• Taking part in code reviews, providing constructive feedback to other team members commits.
• Updating support documentation and providing training to our 1st line teams.

Essential Skills

• Programming/scripting
• Software testing
• Software development lifecycle
• Application development
• Debugging

What we'd like to see on your CV

• Use of distributed data sets (typically using a dataframe) stored on HDFS or CEPHFS, implementation, debug and tuning of queries for performance and resilience.
• Elasticsearch - Configuration, tuning, data discovery and working with large datasets.
• Python3 and pySpark - The majority of our custom code for query is written in python3, using pyspark extensively with jupyter notebooks and Visual Studio Code.
• Scala - For ad-hoc queries and customer insights.
• React, NextJS, MUI - Creating Web based UIs to allow users to query, display and interact with data outputs.
• A working knowledge of ansible and puppet would be advantageous.
• Networking - Experience of protocol analysis and ethernet stacks.
• The ability to build relationships with senior customers and stakeholders.
• Qualified to a degree level or with significant technical experience.

Benefits
At BT, we entertain, educate, and empower millions of people every single day. We're a brand built on connecting people - whether that's friends, family, businesses, or communities. Working here, you'll receive an attractive salary and a range of competitive benefits, but - more than that - you'll be joining an ambitious organisation with a culture of togetherness, collaboration, and inclusivity, that takes a genuine and proactive interest in your progress and development.

• Competitive salary
• 10% on target bonus (Depending on country based)
• BT Pension scheme, minimum 5% Employee contribution, BT contribution 10%
• On-call allowance
• 25 days annual leave (not including bank holidays), increasing with service
• Huge range of flexible benefits including cycle to work, healthcare, season ticket loan
• World-class training and development opportunities
• Option to join BT Shares Saving schemes.
• Discounted broadband, mobile and TV packages
• Access to 100's of retail discounts including the BT shop

#LI-Onsite
Security is one of the fastest growing parts of our global organisation. We are protecting our networks from more than 6,500 cyber attacks each day, investing over xc2xa340m in research each year - and in employing nearly 3,000 people, we're also the largest private cyber employer in the UK. With incredible opportunities to learn, develop and grow your skills, we'll invest in you, nurture your potential and shape your future - whatever your background or experience.
In today's world, safe and secure digital connections have never been more vital. You'll be joining a global company operating at the forefront of the information age: BT employs 90,000 people in 180 countries. With huge scale, we're capable of achieving great things, striving to be personal, simple, and brilliant for our customers whilst creating an inclusive working environment where people from all backgrounds can succeed. Play your part. Make a difference. We are the Protectors.
A FEW POINTS TO NOTE:
Although these roles are listed as full-time, if you're a job share partnership, work reduced hours, or any other way of working flexibly, please still get in touch.
We will also offer reasonable adjustments for the selection process if required, so please do not hesitate to inform us.
DON'T MEET EVERY SINGLE REQUIREMENT?
Studies have shown that women and people who are disabled, LGBTQ+, neurodiverse or from ethnic minority backgrounds are less likely to apply for jobs unless they meet every single qualification and criteria. We're committed to building a diverse, inclusive, and authentic workplace where everyone can be their best, so if you're excited about this role but your past experience doesn't align perfectly with every requirement on the , please apply anyway - you may just be the right candidate for this or other roles in our wider team.