Email Security Software: Compare Business Solutions

The email security software landscape

Email security software has evolved significantly from the days of simple spam filters. Modern solutions address phishing, business email compromise (BEC), malware delivery, account takeover, and data loss — often using machine learning to detect threats that have no known signature. For UK SMEs, the challenge is not a lack of options but understanding which solutions are appropriate for their specific environment.

The starting point is almost always the mail platform itself. Businesses using Microsoft 365 should understand what is included in their existing licence before purchasing additional tools. Those on Google Workspace have a parallel set of native and third-party options. The principle is to build on what you already have before adding new platforms.

Microsoft Defender for Office 365

Microsoft's native email security capability is included in several Microsoft 365 plans and is the most common starting point for UK SMEs.

• Exchange Online Protection (EOP): Included in all Microsoft 365 plans. Provides anti-spam, anti-malware, basic phishing protection, connection filtering and outbound spam control. EOP alone is a reasonable baseline but lacks advanced anti-phishing and sandboxing.
• Defender for Office 365 Plan 1: Included in Microsoft 365 Business Premium (approximately £19.70/user/month in 2026). Adds safe links, safe attachments (sandboxing), anti-phishing policies with impersonation protection, and real-time threat protection dashboards.
• Defender for Office 365 Plan 2: Available in Microsoft 365 E5 or as an add-on to E3. Adds attack simulation training, automated investigation and response, advanced threat hunting, and priority account protection.

For most UK SMEs, Business Premium's Defender Plan 1 provides an adequate foundation when properly configured. The default Microsoft 365 Business Premium configuration does not enable all Defender features — they must be actively configured to be effective.

Mimecast

Mimecast is a widely used third-party email security platform with strong adoption among UK businesses. It operates as a gateway sitting in front of Microsoft 365 or Google Workspace, providing:

• Email filtering, attachment sandboxing and URL inspection
• Targeted threat protection against impersonation and BEC
• Email continuity — maintaining inbox access even during a Microsoft 365 outage
• Email archiving and compliance features
• Brand protection (monitoring of lookalike domain registrations)

Mimecast pricing for SMEs typically starts from £3–£5 per user per month for core email security. The email continuity feature is particularly valued by businesses where email availability is operationally critical. Mimecast is well established in the UK market with local data centres and a strong channel partner network.

Proofpoint Essentials

Proofpoint is a widely respected name in enterprise email security. Proofpoint Essentials targets the SME market with a cloud-based gateway that includes email filtering, targeted attack protection, URL defense, and email archiving. Pricing for SMEs typically starts from £3–£6 per user per month depending on the tier selected.

Proofpoint's threat intelligence is derived from its large enterprise customer base, which provides early visibility into emerging attack campaigns. This is a meaningful differentiator — threats targeting large enterprises often cascade to SMEs, and early detection at the enterprise level benefits smaller organisations on the same platform.

Abnormal Security

Abnormal Security takes a different approach from traditional gateway vendors. Rather than scanning message content for known-bad indicators, it builds a behavioural baseline for every account in the organisation — who communicates with whom, typical email patterns, normal business context — and detects deviations that indicate compromised accounts, BEC and social engineering.

This makes Abnormal particularly effective against the threats that traditional gateways miss: email that contains no malicious links or attachments but uses social engineering to deceive recipients. Pricing positions Abnormal above basic gateway solutions, and it is most compelling for organisations that have already deployed a good gateway and want to close the BEC and account takeover gap.

Barracuda Email Protection

Barracuda offers a comprehensive email security platform that includes gateway filtering, impersonation detection, email archiving and backup, and security awareness training. It is a strong option for organisations wanting a consolidated platform from a single vendor. SME pricing typically starts from £2–£4 per user per month for core protection.

Choosing the right solution for your business

The right choice depends on several factors:

• Existing licensing: If you are already paying for Microsoft 365 Business Premium, maximising Defender's capabilities before adding another licence is sensible
• Risk profile: Financial services, legal, healthcare and construction firms — where email-based fraud is most prevalent and costly — benefit most from additional layers
• IT resource: Solutions with managed services options reduce the configuration and monitoring burden on internal IT teams
• Budget: £3–£6/user/month for a third-party gateway, compared to the average cost of a single successful phishing incident, typically represents a strong return

AMVIA assesses, configures and manages email security solutions for UK businesses, providing advice on the combination of tools that best matches each organisation's environment and risk profile.