diff --git a/app/services/payment_providers/gocardless/payments/cancel_service.rb b/app/services/payment_providers/gocardless/payments/cancel_service.rb
new file mode 100644
index 00000000000..06249b27f38
--- /dev/null
+++ b/app/services/payment_providers/gocardless/payments/cancel_service.rb
@@ -0,0 +1,59 @@
+# frozen_string_literal: true
+
+module PaymentProviders
+  module Gocardless
+    module Payments
+      class CancelService < BaseService
+        Result = BaseResult[:payment]
+
+        def initialize(payment:)
+          @payment = payment
+          super
+        end
+
+        def call
+          gocardless_result = client.payments.cancel(payment.provider_payment_id)
+
+          payment.status = gocardless_result.status
+          payment.payable_payment_status = payment.payment_provider.determine_payment_status(payment.status)
+          payment.save!
+
+          result.payment = payment
+          result
+        rescue GoCardlessPro::InvalidStateError => e
+          # Best-effort cancel only for the documented "cancellation_failed"
+          # case — the payment is in a state that cannot be cancelled
+          # (already submitted, paid out, cancelled, etc.). Log and treat as
+          # a successful no-op so the caller (timeout/expiration flow) does
+          # not block on PSP-side cleanup. The Payment record is left
+          # untouched; the webhook for the prior state transition will land
+          # its true state.
+          #
+          # Other InvalidStateError codes propagate so the caller can retry
+          # or surface the failure.
+          raise unless e.code == "cancellation_failed"
+
+          Rails.logger.info("GoCardless payment not cancelable for payment #{payment.id}: #{e.message}")
+          result.payment = payment
+          result
+        rescue Faraday::ConnectionFailed => e
+          # GoCardless gem surfaces transport errors as raw Faraday
+          # exceptions. Wrap so the caller can retry through the same path
+          # as other PSPs (matches the create-side error handling pattern).
+          raise Invoices::Payments::ConnectionError, e
+        end
+
+        private
+
+        attr_reader :payment
+
+        def client
+          @client ||= GoCardlessPro::Client.new(
+            access_token: payment.payment_provider.access_token,
+            environment: payment.payment_provider.environment
+          )
+        end
+      end
+    end
+  end
+end
diff --git a/spec/services/payment_providers/gocardless/payments/cancel_service_spec.rb b/spec/services/payment_providers/gocardless/payments/cancel_service_spec.rb
new file mode 100644
index 00000000000..043fb82988f
--- /dev/null
+++ b/spec/services/payment_providers/gocardless/payments/cancel_service_spec.rb
@@ -0,0 +1,135 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+RSpec.describe PaymentProviders::Gocardless::Payments::CancelService do
+  subject(:result) { described_class.call(payment:) }
+
+  let(:organization) { create(:organization) }
+  let(:customer) { create(:customer, organization:) }
+  let(:invoice) { create(:invoice, customer:, organization:) }
+  let(:payment_provider) { create(:gocardless_provider, organization:, access_token: "gc_test_token") }
+  let(:provider_customer) { create(:gocardless_customer, customer:, payment_provider:) }
+  let(:payment) do
+    create(:payment, payable: invoice, payment_provider:, payment_provider_customer: provider_customer,
+      organization:, customer:, provider_payment_id: "PM123",
+      payable_payment_status: :pending, status: "pending_submission")
+  end
+
+  let(:gocardless_client) { instance_double(GoCardlessPro::Client) }
+  let(:gocardless_payments_service) { instance_double(GoCardlessPro::Services::PaymentsService) }
+
+  before do
+    allow(GoCardlessPro::Client).to receive(:new).and_return(gocardless_client)
+    allow(gocardless_client).to receive(:payments).and_return(gocardless_payments_service)
+  end
+
+  context "when the payment is cancelable" do
+    let(:cancel_response) do
+      instance_double(GoCardlessPro::Resources::Payment, id: "PM123", status: "cancelled")
+    end
+
+    before do
+      allow(gocardless_payments_service).to receive(:cancel).and_return(cancel_response)
+    end
+
+    it "calls the GoCardless cancel endpoint with the payment's provider id" do
+      result
+
+      expect(gocardless_payments_service).to have_received(:cancel).with("PM123")
+    end
+
+    it "constructs the client with the provider's access token and environment" do
+      result
+
+      expect(GoCardlessPro::Client).to have_received(:new).with(
+        access_token: "gc_test_token",
+        environment: payment_provider.environment
+      )
+    end
+
+    it "returns a successful result with the payment" do
+      expect(result).to be_success
+      expect(result.payment).to eq(payment)
+    end
+
+    it "writes the cancelled status from the response onto the payment" do
+      result
+
+      expect(payment.reload.status).to eq("cancelled")
+    end
+
+    it "maps the cancelled status to a failed payable_payment_status" do
+      result
+
+      expect(payment.reload.payable_payment_status).to eq("failed")
+    end
+  end
+
+  context "when GoCardless raises InvalidStateError with code cancellation_failed" do
+    before do
+      allow(gocardless_payments_service).to receive(:cancel)
+        .and_raise(GoCardlessPro::InvalidStateError.new(
+          "message" => "This payment cannot be cancelled, its status is submitted",
+          "code" => "cancellation_failed"
+        ))
+    end
+
+    it "returns a successful result with the payment" do
+      expect(result).to be_success
+      expect(result.payment).to eq(payment)
+    end
+
+    it "logs the underlying error message" do
+      allow(Rails.logger).to receive(:info)
+
+      result
+
+      expect(Rails.logger).to have_received(:info)
+        .with(a_string_matching(/GoCardless.*not cancelable.*status is submitted/))
+    end
+
+    it "does not mutate the payment record" do
+      expect { result }.not_to change { payment.reload.attributes }
+    end
+  end
+
+  context "when GoCardless raises InvalidStateError with a different code" do
+    before do
+      allow(gocardless_payments_service).to receive(:cancel)
+        .and_raise(GoCardlessPro::InvalidStateError.new(
+          "message" => "Mandate is inactive",
+          "code" => "mandate_is_inactive"
+        ))
+    end
+
+    it "propagates the error so the caller can retry or surface the failure" do
+      expect { result }.to raise_error(GoCardlessPro::InvalidStateError)
+    end
+  end
+
+  context "when GoCardless raises a generic error" do
+    before do
+      allow(gocardless_payments_service).to receive(:cancel)
+        .and_raise(GoCardlessPro::Error.new(
+          "message" => "Internal server error",
+          "code" => "server_error"
+        ))
+    end
+
+    it "propagates the error so the caller can retry" do
+      expect { result }.to raise_error(GoCardlessPro::Error)
+    end
+  end
+
+  context "when a Faraday connection failure occurs" do
+    before do
+      allow(gocardless_payments_service).to receive(:cancel)
+        .and_raise(Faraday::ConnectionFailed.new("connection refused"))
+    end
+
+    it "wraps the error as Invoices::Payments::ConnectionError so the caller can retry" do
+      expect { result }.to raise_error(Invoices::Payments::ConnectionError)
+    end
+  end
+end