Free Writing Prospectus dated June 20, 2018

(to Prospectus dated December 13, 2017 and

Preliminary Prospectus Supplement dated June 20, 2018)

Filed pursuant to Rule 433

Registration Statement No. 333-222022

$750,000,000 aggregate principal amount of Floating Rate Senior Notes due 2024 (the “Floating Rate Notes”).

Three-month U.S. dollar LIBOR plus 1.550% per annum, accruing from the Settlement Date to, but excluding the Maturity Date.

The determination of LIBOR is subject to the provisions/circumstances set forth under “Description of the Senior Notes—Interest—LIBOR Discontinuation” in the prospectus supplement.

Three-month U.S. dollar LIBOR, (Reuters LIBOR01), modified following, adjusted.

The determination of LIBOR is subject to the provisions/circumstances set forth under “Description of the Senior Notes—Interest—LIBOR Discontinuation” in the prospectus supplement. 

The Floating Rate Notes are not redeemable at the option of the holders at any time. RBSG may redeem the Floating Rate Notes at its sole discretion, in whole but not in part on the Optional Redemption Date (as defined in the prospectus supplement) at 100% of their principal amount plus accrued but unpaid interest to, but excluding, the date of redemption. In addition, RBSG may redeem the Floating Rate Notes, in whole but not in part, at 100% of their principal amount plus accrued but unpaid interest to, but excluding, the date of redemption, upon the occurrence of certain tax or regulatory events as described in the prospectus supplement and the accompanying prospectus. See “Description of Debt Securities—Redemption,” “Description of the Senior Notes Loss—Absorption Disqualification Event Redemption” and “Description of the Senior Notes—Tax Redemption” in the prospectus supplement.

Notwithstanding any other provision, RBSG may only redeem the Floating Rate Notes prior to the maturity date or repurchase the Floating Rate Notes (and give notice thereof to the holders of such Floating Rate Notes in the case of redemption), if it has obtained the prior consent of the PRA (as defined in the prospectus supplement), to the extent such consent is at the relevant time and in the relevant circumstances required by the Loss Absorption Regulations (as defined in the prospectus supplement) or applicable laws or regulations in effect in the United Kingdom, if at all, as described in the prospectus supplement under “Description of the Senior Notes—Conditions to Redemption and Repurchase.”

The Floating Rate Notes contain very limited events of default provisions and the remedies available thereunder are limited, as described in the prospectus supplement under “Description of the Senior Notes—Events of Default and Defaults; Limitation of Remedies.”

Notwithstanding any other agreements, arrangements, or understandings between RBSG and any holder or beneficial owner of the Floating Rate Notes, by its acquisition of Floating Rate Notes, each holder and beneficial owner of the Floating Rate Notes acknowledges, accepts, agrees to be bound by and consents to the exercise of any UK bail-in power by the relevant UK resolution authority which may result in (i) the reduction or cancellation of all, or a portion, of the principal amount of, or interest on, the Floating Rate Notes; (ii) the conversion of all, or a portion, of the principal amount of, or interest on, the Floating Rate Notes into ordinary shares or other securities or other obligations of RBSG or another person and/or (iii) the amendment or alteration of the maturity of the Floating Rate Notes, or amendment of the amount of interest due on the Floating Rate Notes, or the dates on which interest becomes payable, including by suspending payment for a temporary period; which UK bail-in power may be exercised by means of variation of the terms of the Floating Rate Notes solely to give effect to the exercise by the relevant UK resolution authority of such UK bail-in power. Each holder and beneficial owner of the Floating Rate Notes further acknowledges and agrees that the rights of the holders and/or beneficial owners under the Floating Rate Notes are subject to, and will be varied, if necessary, solely to give effect to, the exercise of any UK bail-in power by the relevant UK resolution authority.

No repayment of the principal amount of the Floating Rate Notes or payment of interest on the Floating Rate Notes shall become due and payable after the exercise of any U.K. bail-in power by the relevant U.K. resolution authority unless, at the time that such repayment or payment, respectively, is scheduled to become due, such repayment or payment would be permitted to be made by RBSG under the laws and regulations of the United Kingdom and the European Union applicable to RBSG or other members of the Group.

Joint Bookruners and Joint

Lead Managers

NatWest Markets Securities Inc.

Merrill Lynch, Pierce, Fenner & Smith

Incorporated

Citigroup Global Markets Inc.

Goldman Sachs & Co. LLC

Wells Fargo Securities, LLC

An application will be made to list the Floating Rate Notes on the New

York Stock Exchange